Fairy chess games entirely determined by their last move.
by Alain Brobecker

In december 2003, François Labelle wrote a computer program to search for chess games that are completely determined by their last move. With help from Joost de Heer and 3 months of computing, his program was able to search up to ply 11 (he also made partial search for mating moves up to ply 12). This kind of chess problems, especially when ending in mate, interested me strongly and i started to make a compilation of the ones i could find.

You can read about François' very interesting work on his website at: http://wismuth.com/chess/chess.html. It's really the absolute reference for serious considerations about (orthodox) chess statistics, and you'll find more problems there.

I was so interested i started writing my own program in august 2008, so that i was able to make the same work as François, but for various chess variants, since he only used it for orthodox and "one sided" chess.

François' program is better and faster, due to the different method used: As far as i know François records every new position arising in a transposition table, saved on disk, and if the position as already been seen he doesn't process it again. Since every thing is saved he can make further research without generating everything again. My program stupidly generates all chess moves, and thus may well process some positions many times. The advantages relies in the easier design of the program and the lower memory consumption.

Below is a compilation of chess games entirely determined by their last move. Section 1 & 2 are mostly due to François' work. All the problems in section 3 and more were discovered by my program unless otherwise stated (since december 2008 Noam Elkies used Popeye and some sorting tools to do the same or push further some calculations). They are considered as C+ (ie validated by computer), but this assumes the variants have been correctly understood and programmed (and i have in mind some examples i can't boast about). Please do tell me if you find some errors or if you find new problems (using a program or not).

Sometimes you'll find an interrogation mark inside the notations of a move. For example "6.N?d3#" means the ending move is a kNight move to the square d3, but we don't know if a piece has been captured or not. Knowing this i think all stipulations shall be clear: "2.Q?#" means the game ends with a Queen move, possibly a capture. "3.Qx#" means the game ends with a capture by the Queen...

Table of contents:
  1. Orthodox chess problems
  2. One sided chess problems
  3. Dissimilar chess problems (ply 9)
  4. Berolina chess problems (ply 8)
  5. Guardian chess problems (ply 8)
  6. Monochromatic chess problems (ply 10)
  7. Einstein chess problems (ply 8)
  8. Frankfurter chess (Rex exclusive) problems (ply 8)
  9. Chameleon pursuit chess problems (ply 8)
  10. Hypervolage chess problems (ply 8)
  11. Andernach chess problems (ply 8)
  12. Anti-Andernach chess problems (ply 8)
  13. Cardiac chess problems (ply 7)
  14. Grid chess problems (ply 8)
  15. Displaced grid chess problems (ply 8)
  16. Handicap chess problems (ply 7)
  17. Fool's chess (ply 7)
  18. Provocative chess (ply 8)
  19. Patrol chess (ply 7)
  20. Antipatrol chess (ply 7)
  21. Banana skin chess (ply 7)
  22. Baseline chess (ply 7)
  23. Magnetic chess (ply 7)
  24. Air intake chess (ply 8)
  25. Must capture chess (ply 9)
  26. Logical Progressive (ply 10)
  27. Knightmate (ply 7)
  28. Upside down (ply 10)
  29. Nightrider (ply 7)
  30. Kamikaze (ply 9)
  31. Hoppers (ply 8)
  32. Berkeley chess (ply ?)
More variants were tested but since their results were uninteresting (at least up to the tested ply) i didn't include them. Namely they are: bichromatic chess (ply 9), harakiri=kamikaze+square explodes (ply 8).

1. Orthodox chess problems
Most of the problems below are ending in mate, and were discovered with the help of a computer or verified afterward with a computer. Only a few were discovered with brain only i think, and that is amazing: see for example 6.gxf8=N# created by Peter Rösler in 1994!

  1. Find the unique game terminating with 3... Qd4#. (François Labelle, C+)
  2. Find the unique way to bring a black rook to e1 in only 4 moves. (François Labelle, C+)
  3. Find the unique game terminating with 4... Qb5#. (François Labelle, C+)
  4. Find the unique game terminating with 4... b5#. (François Labelle, C+)
  5. *Find the unique game terminating with 5. Ng3#. (François Labelle, C+)
  6. Find the unique game terminating with 5. Qxe4#. (François Labelle, C+)
  7. Find the unique game starting with 1.f3 and finishing by 5... Kf6#. (Peter Rösler, feenschach n°132, 1999)
  8. Find the unique game terminating with 5... N4c6#. (François Labelle, C+)
  9. Find the unique game terminating with 5... N8c6#. (François Labelle, C+)
  10. Find the unique game terminating with 5... Ndc6#. (François Labelle, C+)
  11. Find the unique game terminating with 5... N8h6#. (François Labelle, C+)
  12. Find the unique game terminating with 5... Rh1#. (François Labelle, C+)
  13. Find the unique game in which black mates on his 5th move by moving a rook, but without that rook directly giving check. (François Labelle, C+)
  14. Find the unique game finsihing with the discovered checkmate 5... Rh6#. (François Labelle, C+)
  15. *Find the unique game in which black mates on his 5th move by playing a Bishop from the f2 square. (François Labelle, French Retrograde Analysis Championship in Messigny, may 2004, C+)
  16. ?Find the unique game terminating with 6.gxf8=N#. (Peter Rösler, Problemkiste, 1994/08, C+ by François Labelle)
  17. ?Find the unique game finishing with the direct checkmate 6.Bh7#. (François Labelle, C+)
  18. ?Find the unique game terminating with the double checkmate 6.N?d3#. (François Labelle, C+)
  19. ?Find the 4 games that are identical up to the move 6.Ka5xRa4 and finishing with: a) 9.Nd4xNe2, b) 9... Be2xRg4, c) 10.Rf3xRf1 and d) 10... Qe1xRe7. (Per Ingvar Olin, 3666 Problemkiste 97, 1995/02)
  20. ?Find the 4 games that are identical up to the move 5.Bh8xRa1 and finishing with: a) 8... Qc1xQb1, b) 8... Ra1xNa5, c) 8... Bb1xBg6 and d) 8... Nd1xRe3. (Per Ingvar Olin, 699 Suomen Tehtäväniekat 1995/01)
  21. ?Find the unique game containing 5... e1=N and in which black has no choice but to mate on his 7th move. (Mark Kirtley, Probleemblad 2004/07-08)
  22. ?Find the unique game containing 5.Sc3xTd1 and finishing with 12.Df7xTc4#. (Per Ingvar Olin, Problemkiste 1997)
solutions

2. One sided chess problems
In "one sided chess" (partie de série, ?) only the white player moves. François Labelle again used his program to find all problems completely determined by their last move, up to white's 10th move.

  1. Find the unique "one sided" game terminating with 6.exf8=R#. (François Labelle, C+)
  2. Find the unique "one sided" game terminating with 6.exf8=D#. (François Labelle, C+)
  3. Find the unique "one sided" game terminating with 7.Qxd7#. (François Labelle, C+)
  4. Find the unique "one sided" game in which white plays only one piece and mates on his 8th move. (?Mehr Hovhanisian?)
  5. Find the unique "one sided" game in which white mates on his 8th move by playing a rook from the g8 square. (François Labelle, C+)
  6. Find the unique "one sided" game in which white mates on his 9th move by playing a piece from square d2 to square d8. (François Labelle, C+)
solutions

3. Dissimilar chess problems (ply 9)
In "dissimilar chess" (échecs disparates, Roméo Bédoni, Phénix 134), when a piece has moved, no opponent's piece of same nature can counterstrike. (Alain Brobecker, Jubilé Roméo Bédoni-80, august-september 2008, C+)

  1. Find the unique "dissimilar chess" game terminating with 4... BxNg3#.
  2. Find the unique "dissimilar chess" game terminating with 5.d6#.
  3. Find the unique "dissimilar chess" game terminating with 5.g4#.
  4. *Find the unique "dissimilar chess" game terminating with 5.Bxf5#.
  5. *Find the unique "dissimilar chess" game terminating with 5.Qe3#.
  6. All other problems with similar stipulation up to ply 9, and without castling are terminating with: 5.Bh5xNf7#, 5.Nh4-f5#, 5.Qa4-b4#, 5.Qa4-e4#, 5.Qa5xNe5#, 5.Qb3-b4#, 5.Qb5xNe5#, 5.Qb7xPd7#, 5.Qd3-e4#, 5.Qd3xBf5#, 5.Qe4xNe5#, 5.Qf3-e4#, 5.Qf3xNf5#, 5.Qf4xNe5#, 5.Qf5xNe5#, 5.Qf7-e6#, 5.Qg3xNe5#, 5.Qg4xNf5#, 5.Qh5xNd5#, 5.Qh5xNf5#, 5.Qh5xQd5#.
solutions

4.Berolina chess problems (ply 8)
In "berolina chess" (Edmund Hebermann, 1926) all pawns are assumed to be "berolina pawns": they move one square diagonally forward, or two squares diagonally on their first move. They capture one square straight forward and en passant capture is possible: n.e2-c4 d4xd3 e.p. Only one game is entirely determined by his last mating move up to ply 7. On december 2008 Noam Elkies did the computation up to ply 8 using Popeye, and found only two new problems.

  1. Find the unique game in "berolina chess" terminating with 4.c5#. (Phénix 175, 2008/07)
  2. Find the unique game in "berolina chess" terminating with 4...Qd7?d5. (Noam Elkies)
  3. Find the unique game in "berolina chess" terminating with 4...Qh2:f4. (Noam Elkies)
solutions

5. Guardian chess problems (ply 8)
The baseline of "guardian chess" (George Jeliss, 1982) will be found by answering the following question: What is the unique rearrangement of pieces on their baseline so that every piece (figure or pawn) is guarded at least once and so that Q is on the left of K (from white's viewpoint)?

  1. Find the unique game in "guardian chess" terminating with 3... Qd4#. (Variant Chess 59, 2009/01)
  2. Find the unique game in "guardian chess" in which white mates on his 4th move with a rook. (Variant Chess 59, 2009/01)
  3. Find the unique game in "guardian chess" terminating with 4... Qxg1#. (Variant Chess 59, 2009/01)
  4. All other problems with similar stipulation up to ply 8, and without castling are terminating with: 4.Qa5-d5#, 4.Qb5-d5#, 4.Qb5xPf5#, 4.Qb7-d5#, 4.Qc5-d5#, 4.Qf3xPh5#, 4.Qg5-d5#, 4.Qh3xPh5#, 4... Qf2-d4#, 4... Qg1-d4#.
solutions

6. Monochromatic chess problems (ply 10)
In "monochromatic chess" (origins unknown) pieces can only move to and attack squares of the same colour as the one they stand on. Thus knights cannot move or attack, queenside castling is forbidden, pawns can only make a double step or capture, kings can be on neighbouring squares. Note that pieces on other colored squares intercept attacks of long range pieces anyway. (2008.09.15)

  1. Find the unique "monochromatic chess" game terminating with 2.Q?#.
  2. Find the unique "monochromatic chess" game terminating with 3.B?b5#.
  3. Find the unique "monochromatic chess" game terminating with 4.Bxc6#.
  4. Find the unique "monochromatic chess" game terminating with 4... QxR#.
  5. Find the unique "monochromatic chess" game terminating with 4... Qc1-e1#.
  6. Find the unique "monochromatic chess" game terminating with 5.Qf3-h3#.
  7. Find the unique "monochromatic chess" game terminating with 5.Qc6-e8#. (Die Schwalbe 234, 2008/12)
  8. Find the unique "monochromatic chess" game terminating with 5.Bb7#.
  9. Find the unique "monochromatic chess" game terminating with 5.Be4#.
  10. Find the unique "monochromatic chess" game terminating with 5.Qa6-c8#. (The Problemist v22n1, 2009/01)
  11. Find the unique "monochromatic chess" game terminating with 5... BxN#. (Die Schwalbe 235, 2009/02)
  12. Find the unique "monochromatic chess" game terminating with 5... R?d6#. (Phénix 179, 2008/12)
  13. Find the unique "monochromatic chess" game terminating with 5... Qa5-g5#.
  14. Find the unique "monochromatic chess" game terminating with 5... Be7xPd6#. (Die Schwalbe 234, 2008/12)
  15. Find the unique "monochromatic chess" game terminating with 5... Qf8xPf2#. (Shakhmatnaya Kompozitsiya 2008, 1st prize)
  16. More problems with a small stipulation up to ply 10, without castling or promotion are terminating with: 4.Qxc6#, 4.B?c8#, 4.B?e8#, 4.B?f5#, 4.Q?a4#, 4.Q?e8#, 4... B?g5#, 4... B?e7#, 4... B?f6#, 5.B?e6#, 5... Bxe1#, 5... R?f6#, 5... R?d4#, 5... R?f4#.
  17. All other problems with similar stipulation up to ply 10, without castling or promotion are terminating with: 3... Ba3xBb4#, 3... Bc5xBb4#, 3... Bd6xBb4#, 3... Be7xBb4#, 3... Qa5xBb4#, 3... Qb6xBb4#, 3... Qd6xBb4#, 3... Qe7xBb4#, 3... Qf6-f4#, 3... Qg5xPf4#, 3... Qh4-f4#, 3... Qh4xPf4#, 4.Ba4xBb5#, 4.Ba8-c6#, 4.Bb7-d5#, 4.Bc6-d5#, 4.Qa6-c6#, 4.Qa6xPb5#, 4.Qb7-d5#, 4.Qb7xBb5#, 4.Qb7xPd5#, 4.Qc4xPd5#, 4.Qd5xBb5#, 4.Qe4xPd5#, 4.Qf3-d5#, 4.Qh7-f5#, 4... Ba3-d6#, 4... Bb2xPd4#, 4... Bb4-d6#, 4... Bb6xPd4#, 4... Bc3xPd4#, 4... Bc5-d6#, 4... Be7-d6#, 4... Qe1-g3#, 4... Qe1xBc1#, 4... Qe7-f6#, 4... Qe7-g5#, 4... Qe7xPe5#, 4... Qf2xBf4#, 4... Qg5-f6#, 4... Qh4-f6#, 5.Ba8xPd5#, 5.Bb7-f3#, 5.Bc6-f3#, 5.Bd5-f3#, 5.Bd5xPe4#, 5.Be2-f3#, 5.Be4-f3#, 5.Bh5-f7#, 5.Qb5-e2#, 5.Qc4-e2#, 5.Qd1-e2#, 5.Qe2-d3#, 5.Qh5-f7#, 5.Qh5-g4#, 5.Qh5-h3#, 5... Bb6xPc5#, 5... Bc1-a3#, 5... Bf4-d6#, 5... Bg3-d6#, 5... Bh2-d6#, 5... Qa1-f6#, 5... Qb6xBe3#, 5... Qc1xPb2#, 5... Qc5xBe3#, 5... Qe5-c7#, 5... Qe7-a3#, 5... Qf4-c7#, 5... Qf6-d8#, 5... Qg3-c7#, 5... Qg5-d8#, 5... Qh2-c7#, 5... Qh4-d8#, 5... Qh4xBg3#, 5... Qh6-d2#, 5... Rd6-b6#, 5... Rd6-h6#, 5... Rf6-b6#, 5... Rf6-h6#.
solutions

7. Einstein chess problems (ply 8)
In "Einstein chess" (Adam & Barthommier, 1981) a piece other than K is demoted each time it moves without capturing (Q>R>B>N>P>P) and promoted each time it captures (P>N>B>R>Q>Q). Castling demotes R to B. No conventionnal 8th rank promotion, Ps act as block on 8th rank. Pawns on the 1st rank (after a N has moved there without capturing) can make a double or triple step advance, with related en passant capture. Please note that Noam Elkies discovered the same problems with the same method (ie exhaustive computer testing) and published them around the same time (Variant Chess 59, January 2009, my own computer's output being dated 2008.09.16).

  1. Find the unique "Einstein chess" game terminating with 4.Q?f5#.
  2. Find the unique "Einstein chess" game terminating with 4... QxNf4#.
  3. Find the unique "Einstein chess" game terminating with 4... P?c4#. (Mémorial Jean Michel Trillon)
  4. Find the unique "Einstein chess" game terminating with 4... BxP#. (Phénix 179, 2008/12)
  5. Find the unique "Einstein chess" game terminating with 4... PxP=Nep#. (The Problemist v22n1, 2009/01 & Noam Elkies, Variant Chess 59, 2009/01)
  6. Find the unique "Einstein chess" game terminating with 5.B???d3#. (Noam Elkies)
  7. Find the unique "Einstein chess" game terminating with 5.R??-e4=B#. (Noam Elkies)
  8. Find the unique "Einstein chess" game terminating with 5.Qc8?e6(??)#. (Noam Elkies)
  9. Find the unique "Einstein chess" game terminating with 5.Qe3?e5(??)#. (Noam Elkies)
  10. Find the unique "Einstein chess" game terminating with 5.Qh7-e4=R#. (Noam Elkies)
  11. All other problems with similar stipulation up to ply 8, and without castling are terminating with: 3... Rf6xPf4#, 3... Rh4xPf4#, 4.Rd5xPe5#, 4... Re6xPe4#.
solutions

8. Frankfurter chess (Rex exclusive) problems (ply 8)
In "Frankfurter chess (Rex exclusive)" (?, feenschach 1959/01) any capturing man except the king assumes the power of its victim. A pawn capturing on the 8th rank takes the power of the captured piece.

  1. Find the unique game in "Frankfurter chess (Rex exclusive)" terminating with 4.P?c8#.
  2. Find the unique game in "Frankfurter chess (Rex exclusive)" terminating with 4... RxQ#.
  3. All other problems with similar stipulation up to ply 8 are: 3... Q?d4#, 3... Qb6-b4#, 3... Qf6-f4#, 3... Qh4-f4#, 4.Qf4-f5#, 4.Qg5-f5#, 4.Qc5-f5#, 4.Qa5-f5#, 4.Qg5-d5#, 4.Qa5-c5#, 4.Qg5-c5#, 4.Qc4-c5#, 4.Qb5-g5#, 4.Qb5-c5#, 4.Qf5-c5#, 4.Qg3-g5#, 4.Qb4-b5#, 4.Qa5-d5#, 4... Qa3-b4#, 4... Qg5-c5#, 4... P?b5#, 4... Q?b5#, ... Qb4xQg4#, 4... Qg6xQg4#.
solutions

9. Chameleon pursuit chess problems (ply 8)
In "chameleon pursuit chess" (Lev Grolman, The Problemist 2008/09) if a square vacated on one move is occupied on the following move by an opponent piece other than King, this piece changes colour. Up to ply 8, there are 49 games entirely determined by their last mating move, but only two directly use the fairy condition. Others may use it by omission, ie the mate wouldn't be unique in orthodox chess.

  1. Find the unique game in "chameleon pursuit chess" terminating with 4.Pg6xPf7#. (The Problemist v22n1, 2009/01)
  2. Find the unique game in "chameleon pursuit chess" terminating with 4... Bb6xPf2#. (The Problemist v22n1, 2009/01)
  3. All other problems with similar stipulation up to ply 8 are: 3... Q-d4#, 3... Qb6-b4#, 3... Qf6xPd4#, 3... Qf6-f4#, 3... Qh4-f4#, 3... Qb6xPd4#, 3... Qd5-e4#, 3... Qh4-e4#, 3... Qf6xPf4#, 3... Qg5xPf4#, 3... Qh4xPf4#, 4.Qg5-d5#, 4.Qb5xPf5#, 4.Qg7-e5#, 4.Qf4-f5#, 4.Qh7-f5#, 4.Qg5-f5#, 4.Qc5-f5#, 4.Qa5-f5#, 4.Qa5-c5#, 4.Qg5-c5#, 4.Qc4-c5#, 4.Qb5-g5#, 4.Qb5-c5#, 4.Qf5-c5#, 4.Qg3-g5#, 4.Qb7-d5#, 4.Qa5-d5#, 4.Qb4-b5#, 4... P?b5#, 4... Q?b5#, 4... Qc4xPf4#, 4... Qa4xPf4#, 4... Qa1xBc1#, 4... Qa3-b4#, 4... Qg5-c5#, 4... Qb4xBf4#, 4... Qh2xBf4#, 4... Qb4xQg4#, 4... Qg6xQg4#, 4... Qb5xBc4#, 4... Qa4xBc4#, 4... Qg4xBc4#, 4... Qc5xBc4#, 4... Qb4xBc4#, 4... Qf4xBc4#, 4... Qa6xBc4#.
solutions

10. Hypervolage chess problems (ply 8)
In "hypervolage chess" (A. Davaine, 1969) a unit other than a King changes colour when it moves to a square of a different colour than the one it was standing on.

  1. Find the unique "hypervolage chess" game terminating with 2... exd1=R#.
  2. Find the unique "hypervolage chess" game terminating with 3... Qxc3#.
  3. Find the unique "hypervolage chess" game terminating with 3... B?a6#.
  4. Find the unique "hypervolage chess" game terminating with 3... Qh1xPe4#.
  5. Find the unique "hypervolage chess" game terminating with 4.BxNa3#.
  6. Find the unique "hypervolage chess" game terminating with 4.P?e3#.
  7. Find the unique "hypervolage chess" game terminating with 4.Bh3xPd7#.
  8. Find the unique "hypervolage chess" game terminating with 4... QxQg3#.
  9. Find the unique "hypervolage chess" game terminating with 4... Rg7-g1#.
  10. Find the unique "hypervolage chess" game terminating with 4... Bh6-e3#.
  11. Find the unique "hypervolage chess" game terminating with 4... Bd1xPe2#. (Phénix 189, 2009/11)
  12. Find the unique "hypervolage chess" game terminating with 4... Qa7xPd4#.
  13. Find the unique "hypervolage chess" game terminating with 4... Qa3-a5#.
  14. Find the unique "hypervolage chess" game terminating with 4... Qa3xPb2#.
  15. All other problems with similar stipulation up to ply 8 are: 3... Qxd4#, 3... B?b5#, 3... B?c4#, 3... B?d3#, 3... Q-d4#, 4... QxBg3#, 3... Qb1xPe4#, 3... Qd4xBd2#, 3... Qd6xBd2#, 3... Qf6xPf4#, 3... Qg5-f4#, 3... Qg5xPf4#, 3... Qh4-f4#, 3... Qh4xPf4#, 4.Qb5-f5#, 4.Qb5xPf5#, 4.Qb7-d5#, 4.Qb7xPd5#, 4.Qc4-d5#, 4.Qc4xPd5#, 4.Qe4-d5#, 4.Qe4xPd5#, 4... Qb6-d6#, 4... Qc6-e4#, 4... Qd5-e4#, 4... Qd5xPe4#, 4... Qe1-g3#, 4... Qf5-e4#, 4... Qf5xPe4#, 4... Qf6-d6#, 4... Qf8-f2#, 4... Qg3-e3#, 4... Qg6-e4#, 4... Qg7xPd4#.
solutions

11. Andernach chess problems (ply 8)
In "Andernach chess" (origins unknown) a unit other than King changes color when making a capture. (triple step option, as in "anti-Andernach" was forgotten).

  1. Find the unique game in "Andernach chess" terminating with 4... Qc7-c4#.
  2. Find the unique game in "Andernach chess" terminating with 4... Qd7-d4#.
  3. All other problems with similar stipulation up to ply 8 are: 3... Q?d4#, 3... Qb6-b4#, 3... Qf6-f4#, 3... Qh4-f4#, 4.Qb4-b5#, 4.Qa5-d5#, 4.Qa5-c5#, 4.Qg5-c5#, 4.Qc4-c5#, 4.Qb5-g5#, 4.Qb5-c5#, 4.Qf5-c5#, 4.Qg3-g5#, 4.Qf4-f5#, 4.Qg5-f5#, 4.Qc5-f5#, 4.Qa5-f5#, 4.Qg5-d5#, 4... P?b5#, 4... Qa3-b4#, 4... Qg5-c5#, 4... Qh3-g4#.
solutions

12. Anti-Andernach chess problems (ply 8)
In "anti-Andernach chess" (origins unknown) a unit other than King changes color when making a move without capture. Pawns on the 1st rank (after a non capturing move) can make a double or triple step advance, with related en passant capture.

  1. Find the unique "anti-Andernach chess" game terminating with 3.Bg6xPf7#.
  2. Find the unique "anti-Andernach chess" game terminating with 3... N?h2#.
  3. Find the unique "anti-Andernach chess" game terminating with 3... RxQc1#.
  4. Find the unique "anti-Andernach chess" game terminating with 3... Qc1xPc3#.
  5. Find the unique "anti-Andernach chess" game terminating with 4.B?b4#
  6. Find the unique "anti-Andernach chess" game terminating with 4... PxBe6#
  7. Find the unique "anti-Andernach chess" game terminating with 4... BxRf2#
  8. Find the unique "anti-Andernach chess" game terminating with 4...NxBf3#
  9. Find the unique "anti-Andernach chess" game terminating with 4... NxRh2#
  10. All other problems with similar stipulation up to ply 8 are: 4.QxRg6#, 4.Bf8xPa3#, 4.Rh8xBf8#, 4.Bf8xNa3# , 4... PxBc6#, 4... QxNd4#, 4... B?d3#, 4... BxQc4#, 4... BxQb5#, 4... Qa4xPa5#, 4... Rd7xQd1#, 4... Qa4xBd4#, 4... Qg4xBd4#, 4... Qd4xRd1#, 4... Qd5xRd1#, 4... Qd6xRd1#, 4... Qb1xPc2#, 4... Qc1xPc2#, 4... Qe6xBe4#, 4... Qc1xPe3#, 4... Rf7xBf1#, 4... Qh7xRh4#, 4... Qh8xRh4#, 4... Rg1xPg2#, 4... Qg1xPg2#.
solutions

13. Cardiac chess problems (ply 7)
In "cardiac chess" (or "check chess" or "presto chess", Frank Hopkins, 1916), the first player to give check wins the game.

  1. Find the unique "cardiac chess" game terminating with 3.Q-e4+.
  2. Find the unique "cardiac chess" game terminating with 3... B?b3+.
  3. Find the unique "cardiac chess" game terminating with 3... R?e5+.
  4. Find the unique "cardiac chess" game terminating with 3... Bh6-g7+.
  5. Find the unique "cardiac chess" game terminating with 4.Qd6-e5+.
  6. Find the unique "cardiac chess" game terminating with 4.Qd6xBe6+.
  7. Find the unique "cardiac chess" game terminating with 4.Qe4xNe7+.
  8. All other problems with similar stipulation up to ply 7 are: *3.Q?d6+, *3.Q-e5+, *3.Q?f8+, 3.Qd2-e3+, 3.Qd3xPe4+, 3.Qd3-e3+, 3.Qd3xPf5+, 3.Qb3xPd5+, 3.Qa4xPe4+, 3.Qf3xPe4+, 3.Qg4xPe4+, 3.Qf3xPd5+, 3.Qf3-f7+, 3.Bh3-e6+, 3.Ne4xQd6+, 3.Nc4xQd6+, *3... B?f6+, 3... Ne5xNd3+, 3... Rh6xPe6+, 3... Qb6-c7+, 3... Qd7-d6+, 3... Be7-d6+, 3... Bb4-d6+, 3... Ba3-d6+, 3... Bh6-f4+, 3... Qg5-e5+, 3... Ra6xPe6+, 3... Qb6xPe6+, 3... Qd6xPe6+, 3... Qd5-c4+, 3... Qd5-f3+, 3... Qd5-h5+, 3... Qd5-d3+, 3... Qd5-b5+, 3... Qf6xBc3+, 3... Qf6xQc3+, 3... Bd6-e5+, 3... Bh6-g7+, 4.Ra6xPd6+, 4.Ra6-d6+, 4.Ra6xPf6+, 4.Ra6-f6+, 4.Bb6xQc7+, 4.Qd6xQc7+, 4.Qd6-c7+, 4.Qd6xQb6+, 4.Qd4xBg4+, 4.Qd4xNe5+, 4.Qd5xNe5+, 4.Qd6xNe5+, 4.Qd6xQf6+, 4.Qd4xBe5+, 4.Qd5xBe5+, 4.Qd6xPc6+, 4.Qe4xQe7+, 4.Qe4xBe7+, 4.Qb7xQb6+, 4.Qf6-f3+, 4.Qe5-e4+, 4.Bh5-f3+, 4.Bg6-e4+, 4.Bh7-e4+, 4.Qd4xNd7+, 4.Qd4xBd7+, 4.Qd4xQd7+, 4.Qc6-c3+, 4.Qc5-d4+, 4.Rh6xPd6+, 4.Rh6-d6+, 4.Rh6xPf6+, 4.Rh6-f6+, 4.Ne7xBc8+, 4.Ne7-f5+, 4.Ne7xNg8+, 4.Ne7-d5+, 4.Nd7xBf8+, 4.Nd7-c5+.
solutions

14. Grid chess problems (ply 8)
In "grid chess" (Walter Stead, Fairy Chess Review 1953/08) the board is divided by 3 horizontal and 3 vertical lines into sixteen 2x2 squares (eg a1+a2+b1+b2 is one). When a man moves it must cross at least one grid line. So opposing men sharing the same 2x2 square have no effect on each other (so the kings can be adjacent). A wing pawn can never move beyond the 5th rank and K cannot reach corner squares. K+R cannot mate K.

  1. Find the unique "grid chess" game terminating with 4.Q?d5#.
  2. Find the unique "grid chess" game terminating with 4.Qf3-b3#.
  3. Find the unique "grid chess" game terminating with 4... Qxe4#. (Phénix 183, 2009/04)
  4. Find the unique "grid chess" game terminating with 4... Nd6-f5#.
  5. Find the unique "grid chess" game terminating with 4... Bb2-d4#.
  6. Find the unique "grid chess" game terminating with 4... Qf5-c5#.
  7. All other problems with similar stipulation up to ply 8 are: 4... Qc7-b6#, 4... Qb2-d4#, 4... Qb2-b6#, 4... Qe6-b6#, 4... Qc6-b6#, 4... Qe4-d4#.
solutions

15. Displaced grid chess problems (ply 8)
In "displaced grid chess" (or "DG chess", Doug Grant, Nost-algia no 168, 1974) is a form of grid chess in which the grid lines are displaced by one rank and one file (so producing four 1x1 cells in the corners, six 1x2 and six 2x1 cells on the edges, and nine 2x2 cells in the centre). Now kings can reach the corners and wing pawns are no more blocked. K+R still cannot mate K.

  1. Find the unique "displaced grid chess" game terminating with 2.Q?#.
  2. Find the unique "displaced grid chess" game terminating with 3.Qx#
  3. Find the unique "displaced grid chess" game terminating with 3... QxQ#
  4. Find the unique "displaced grid chess" game terminating with 3.Nd5-c7#
  5. Find the unique "displaced grid chess" game terminating with 4.B?g5#
  6. Find the unique "displaced grid chess" game terminating with 4... BxBb4#
  7. Find the unique "displaced grid chess" game terminating with 4... Qg3xNc3#
  8. Find the unique "displaced grid chess" game terminating with 5.PxR#
  9. Find the unique "displaced grid chess" game terminating with 5.P-f6#
  10. Find the unique "displaced grid chess" game terminating with 5.Pxf6#
  11. Find the unique "displaced grid chess" game terminating with 5.Qxe4#
  12. Find the unique "displaced grid chess" game terminating with 5.R?e3#
  13. Find the unique "displaced grid chess" game terminating with 5.Qf3xQf7#
  14. Find the unique "displaced grid chess" game terminating with 5.Ng8xQf6#
  15. All other problems with similar stipulation up to ply 8 are: 3.Nd5xQc7#, 3.Ne4-f6#, 3.Nd5xPc7#, 3.Nd5-f6#, 3... Nd4xQf3#, 3... Ne5xQf3#, 3... Qf6xPf4#, 3... Qh4xPf4#, 4.N?e5#, 4.BxR#, 4.Qa6xQc8#, 4.Qh6xPh5#, 4.Qd6xPe5#, 4.Qe6xQc8#, 4.Qb5xPf5#, 4.Qh7-h5#, 4.Nh5xQf6#, 4.Nd7xQf6#, 4.Ng4xQf6#, 4... B?f5#, 4... N?c6#, 4... P?c5#, 4... BxQg4#, 4... P?e5#, 4... P?d5#, 4... Qh7-h4#, 4... Qg3-c3#, 5.R?e4#, 5.Rc6xQc8#, 5.Ra8xBc8#, 5.Qc6xQc8#, 5.Bh6xQg5#, 5.Qh3xQh5#, 5.Qe2xNb5#, 5.Qh5xNb5#, 5.Qf3xNf5#, 5.Qh5xNf5#, 5.Be2xBb5#, 5.Qd2xNd7#.
solutions

16. Handicap chess problems (ply 7)
In "handicap chess" (origins unknown) a player removes one of his piece in order to balance the game. It may be specified if the piece given is a pawn or a figure.

  1. White gave a unit and won by 3.Bxg6#. Which unit was given? Game score?
  2. White gave a unit and won by 3.Qg7xPe5#. Which unit was given? Game score?
  3. White gave a unit but lost by 3... QxQd4#. Which unit was given? Game score?
  4. White gave a unit but lost by 3... Qa5-b4#. Which unit was given? Game score?
  5. White gave a unit and won by 4.P?e5#. Which unit was given? Game score?
  6. White gave a unit and won by 4.P?d5#. Which unit was given? Game score?
  7. *White gave a unit and won by 4.Bc6#. Which unit was given? Game score?
  8. White gave a unit and won by 4.Q?g3#. Which unit was given? Game score?
  9. White gave a unit and won by 4.Qg4-f5#. Which unit was given? Game score?
  10. White gave a unit and won by 4.Qa8xPd5#. Which unit was given? Game score?
  11. White gave a unit and won by 4.Ra3-g3#. Which unit was given? Game score?
  12. White gave a unit and won by 4.Rh3-g3#. Which unit was given? Game score?
  13. White gave a unit and won by 4.Qd5xRh5#. Which unit was given? Game score?
  14. White gave a unit and won by 4.Qg8-g5#. Which unit was given? Game score?
  15. White gave a unit and won by 4.Qb8-b5#. Which unit was given? Game score?
  16. White gave a unit and won by 4.Qe5xNh5#. Which unit was given? Game score?
  17. White gave a unit and won by 4.Qf1-b5#. Which unit was given? Game score?
solutions

17. Fool's chess problems (ply 8)
The baseline of "fool's chess" (John Beasley, Variant Chess 59, 2009) will be found by answering the following question: What is the unique rearrangement of pieces on their baseline with normal reflective symmetries (K-side mirrors Q-side, Black mirrors White on the file) which allows a Fool's Mate on White's second move?

  1. Find the unique "fool's chess" game terminating with 3... Qc6xPe4#.
  2. Find the unique "fool's chess" game terminating with 4.Q?f7#. (Variant Chess 60, 2009/04)
  3. Find the unique "fool's chess" game terminating with 4... R?e1#. (Variant Chess 60, 2009/04)
  4. Find the unique "fool's chess" game terminating with 4... R?e4#. (Variant Chess 60, 2009/04)
  5. Find the unique "fool's chess" game terminating with 4... B?c4#. (Variant Chess 60, 2009/04)
  6. Find the unique "fool's chess" game terminating with 4... Qd3xBh3#.
  7. Find the unique "fool's chess" game terminating with 4... Qh6xPh2#.
  8. Find the unique "fool's chess" game terminating with 4... Bd7-h3#.
  9. All other problems with similar stipulation up to ply 8 are: 3... Q-e4#, 3... Q?c4#, 3... Qc6xPe4#, 3... Qg4xPe4#, 4.Qa7-c5#, 4.Qd4-d5#, 4.Qa5-d5#, 4.Qf3-d5#, 4.Qf5-c5#, 4.Qh5-c5#, 4.Qh5-e5#, 4.Qd5-e5#, 4.Qc5-e5#, 4.Qb5-e5#, 4... Rxe5#, 4... Qa4xBd4#, 4... Qd5xBd4#, 4... Qf6xBd4#, 4... Qc4-d4#, 4... Qg6-h6#, 4... Qc5-e5#, 4... Qa5-f5#, 4... Qc5-f5#, 4... Qe5-d4#, 4... Qc4xRe2#, 4... Qc4xPe4#, 4... Qb5xRe2#. .
solutions

18. Provocative chess problems (ply 8)
In "provocative chess" (échecs provocateurs, Roméo Bédoni, Phénix 2002), a piece can capture only when observed by an ennemy piece. There is only one uniquely determined problem up to ply 8.

  1. Find the unique game in "provocative chess" (or in "cardiac chess") terminating with 3... NexNd#.
  2. Find the unique game in "provocative chess" terminating with 5.PxB=R. (François Labelle, 6th commendation, French tourney 2008-2009, Retro section)
  3. In "provocative chess", what is the unique setup of officers in their baseline, amongst the 4!=24 possible ones, so that the white king is on the right of the white queen, that the queenside reflects the kingside, that black pieces are on the same file as white ones and such that white can win by the move 4.NxRe6# ? Game score? (Alain Brobecker, 5th commendation, French tourney 2008-2009, Retro section)
  4. In "provocative chess", what is the unique setup of officers in their baseline, amongst the 4!=24 possible ones, so that the white king is on the right of the white queen, that the queenside reflects the kingside, that black pieces are on the same file as white ones and such that white can win by the move 3... .NxRh3# ? Game score? (2008.12.07)
  5. handicap piece 3... Qb6-b4#, -WPd2, 1.Kd2 c5 2.Kc3 Qb6 3.Kb3 Qb4#
  6. handicap piece 3... Qa5-b4#, -WPd2, 1.Kd2 c5 2.Kc3 Qa5 3.Kb3 Qb4#
  7. handicap piece 4.Q?d6#, -WPd2, 1.Be3 e5 2.Bb6 Ke7 3.Bxc7 Qe8 4.Qd6# (also orthodox mate)
  8. handicap piece 4.Qb7-c6#, -WPe2, 1.Qf3 b6 2.Qb7 d5 3.Bb5 Kd7 4.Qc6#
  9. handicap piece 4.Qc5-c6#, -WPe2, 1.Qh5 b6 2.Qc5 e5 3.Bb5 Kd7 4.Qc6#
solutions

19. Patrol chess problems (ply 7)
In "patrol chess" (?), a piece can capture only when observed by a friendly piece.

  1. Find the unique game in "patrol chess" terminating with 4.B?c4#.
  2. Find the unique game in "patrol chess" terminating with 4.Pc3-c4#.
  3. All other problems with similar stipulation up to ply 7 are: 4.Qf5-e5#, 4.Qe4-e5#, 4.Qb7-b5#, 4.Qb4-b5#, 4.Pe3-e4#, 4.Qc4xPd5#, 4.Qg4xPf5#.
solutions

20. Antipatrol chess problems (ply 7)
In "antipatrol chess" (or lortap), a piece can capture only when not observed by a friendly piece.

  1. Find the unique game in "antipatrol chess" terminating with
  2. 3.Qb3-e6#;rnbq1bnr/ppppkppp/8/4p3/8/1QP5/PP1PPPPP/RNB1KBNR
  3. 3.Qf3-f7#;rnbqkbnr/ppppp1pp/8/8/4p3/5Q2/PPPP1PPP/RNB1KBNR
  4. 3... Qb6-d4#;rnb1kbnr/pp1ppppp/1qp5/8/8/4KP2/PPPPP1PP/RNBQ1BNR
  5. 3... Qf6-d4#;rnb1kbnr/pppp1ppp/4pq2/8/8/4KP2/PPPPP1PP/RNBQ1BNR
  6. 3... Qh4-d4#;rnb1kbnr/pppp1ppp/4p3/8/7q/4KP2/PPPPP1PP/RNBQ1BNR
  7. 3... Qg5xPf4#;rnb1kbnr/pppp1ppp/4p3/6q1/5P2/5K2/PPPPP1PP/RNBQ1BNR
  8. 3... Qh4xPf4#;rnb1kbnr/pppp1ppp/4p3/8/5P1q/5K2/PPPPP1PP/RNBQ1BNR
  9. 3... Ne5xNd3#;r1bqkbnr/pppppppp/8/4n3/8/3N4/PPPPPPPP/RNBQKB1R
  10. 3... Nd4xRf3#;r1bqkbnr/pppppppp/8/8/P2n4/5R2/1PPPPPPP/1NBQKBNR
  11. 3... Ne5xRf3#;r1bqkbnr/pppppppp/8/4n3/P7/5R2/1PPPPPPP/1NBQKBNR
  12. 3... Qb6-b4#;rnb1kbnr/pp1ppppp/1qp5/8/8/2KP4/PPP1PPPP/RNBQ1BNR
  13. 3... Qd6-b4#;rnb1kbnr/ppp1pppp/3q4/3p4/8/2KP4/PPP1PPPP/RNBQ1BNR
  14. 3... Qd6-f4#;rnb1kbnr/ppp1pppp/3q4/3p4/8/3PK3/PPP1PPPP/RNBQ1BNR
  15. 3... Qf6-f4#;rnb1kbnr/pppp1ppp/4pq2/8/8/3PK3/PPP1PPPP/RNBQ1BNR
  16. 3... Qh4-f4#;rnb1kbnr/pppp1ppp/4p3/8/7q/3PK3/PPP1PPPP/RNBQ1BNR
  17. *4.Q?c7#;rnb1qbnr/pppkpppp/8/3P4/8/8/PPQPPPPP/RNB1KBNR
  18. 4.Qg8xPg6#;rnbqkbQr/ppppp2p/5np1/5p2/8/2P5/PP1PPPPP/RNB1KBNR
  19. 4.Qg8-g6#;rnbqkbQr/ppppp2p/5n2/5pp1/8/2P5/PP1PPPPP/RNB1KBNR
  20. 4.Qf4xPf5#;rnbq1bnr/ppppp1pp/5k2/5p2/5Q2/2P5/PP1PPPPP/RNB1KBNR
  21. 4.Qa6xPd6#;rnb1qbnr/pppkpppp/Q2p4/8/3P4/8/PPP1PPPP/RNB1KBNR
  22. 4.Qd1-d5#;rnbq1bnr/ppppp1pp/3Pkp2/8/8/8/PPP1PPPP/RNBQKBNR
  23. 4.Qd4xPg7#;rnb1qbnr/pppppkpp/8/3P1p2/3Q4/8/PPP1PPPP/RNB1KBNR
  24. 4.Qc5-f5#;rnbq1bnr/ppp1pppp/3pk3/2Q5/8/4P3/PPPP1PPP/RNB1KBNR
  25. 4.Qe5xPd5#;rnb1qbnr/pppkpppp/8/3pQ3/8/4P3/PPPP1PPP/RNB1KBNR
  26. 4.Qf4xPd6#;rnb1qbnr/pppkpppp/3p4/8/4PQ2/8/PPPP1PPP/RNB1KBNR
  27. 4.Qd5-d6#;rnb1qbnr/pppkpppp/8/3Q4/4P3/8/PPPP1PPP/RNB1KBNR
  28. 4.Qd5-c5#;rnbq1bnr/pppp1ppp/3kp3/3Q4/4P3/8/PPPP1PPP/RNB1KBNR
  29. 4.Qg7xPf6#;rnbq1bnr/ppppp1Qp/4kp2/8/4P3/8/PPPP1PPP/RNB1KBNR
  30. 4.Qf6xPg6#;rnbqkbnr/ppppp2p/5Qp1/8/4p3/8/PPPP1PPP/RNB1KBNR
  31. 4.Nh5xRf6#;1nbqkbnr/1ppppppp/5r2/p6N/8/8/PPPPPPPP/RNBQKB1R
  32. 4.Nd7xRf6#;1nbqkbnr/1ppNpppp/5r2/p7/8/8/PPPPPPPP/RNBQKB1R
  33. 4.Ng4xRf6#;1nbqkbnr/1ppppppp/5r2/p7/6N1/8/PPPPPPPP/RNBQKB1R
  34. All other problems with similar stipulation up to ply 7 are:
solutions

21. Banana skin chess problems (ply 7)
In "banana skin chess" (Jaime Poniachik, Variant Chess 18, 1995) all men except Ks and Ns move to the limit possible, thus white's first move of a pawn would be to the 6th rank.

  1. Find the unique "banana skin chess" game terminating with 2.?# (unique fool's mate)
  2. Find the unique "banana skin chess" game terminating with 2... Qd8-a5#
  3. Find the unique "banana skin chess" game terminating with 3.Qe2-h5#
  4. Find the unique "banana skin chess" game terminating with 3... QxB#
  5. Find the unique "banana skin chess" game terminating with 3... Ra4xPe4#
  6. Find the unique "banana skin chess" game terminating with 4.Q?d5#
  7. Find the unique "banana skin chess" game terminating with 4.B?h3#
  8. Find the unique "banana skin chess" game terminating with 4.Q?d7#
  9. Find the unique "banana skin chess" game terminating with 4.Q?a5#
  10. Find the unique "banana skin chess" game terminating with 4.N?e4#
  11. Find the unique "banana skin chess" game terminating with 4.Q-e5#
  12. Find the unique "banana skin chess" game terminating with 4.Q-e2#
  13. Find the unique "banana skin chess" game terminating with 4.Qxb5#
  14. Find the unique "banana skin chess" game terminating with 4.Q-d8#
  15. Find the unique "banana skin chess" game terminating with 4.QxNe5#
  16. Find the unique "banana skin chess" game terminating with 4.QxQe2#
  17. Find the unique "banana skin chess" game terminating with 4.Qb4-a4#
  18. Find the unique "banana skin chess" game terminating with 4.Qg6xNc6#
  19. All other problems with similar stipulation up to ply 7 are: 3... Qd8xPa5#, 3... Qb6-a5#, 3... Pc2xQd1=?#, 3... Qd2xQd1#, 3... Pg2xBf1=?#, 3... Qf6xNh4#, 3... Rh4xPe4#, 4.Qb5xPe5#, 4.Qd4xPe5#, 4.Qe4xPe5#, 4.Qh3xPe3#, 4.Qc3xNc6#, 4.Qb7xNc6#, 4.Qb7xPc6#, 4.Qd3xPe3#, 4.Qa6xQc8#, 4.Qh4xQd8#, 4.Qd5-e5#, 4.Qd6xPe5#, 4.Qd5xPe5#, 4.Qg5xNh5#, 4.Qh6xPe3#, 4.Qb6-e3#, 4.Qh6-g6#, 4.Qe5xNh5#, 4.Qh5xNf7#, 4.Qh3xNh5#, 4.Qf5xNh5#, 4.Qd1-d5#, 4.Qd1-e2#, 4.Bf1-h3#, 4.Qc2-g6#, 4.Qd7xPf7#, 4.Qe2xPe3#, 4.Bd5-f7#, 4.Qh8xPe5#, 4.Qb3xPa4#, 4.Qg4-a4#, 4.Qg4xQc8#, 4.Qd2-e3#.
solutions

22. Baseline chess problems (ply 7)
What is the unique rearrangement of pieces on their baseline with normal reflective symmetries (K on e-h, Q-side mirrors K-side, Black mirrors White on the file) which allows

  1. 3... Qa6xPh6#
  2. 3... Rb6xPh6#
  3. 3... Rg6xPh6#
  4. 3... Qh3xBg2#
  5. 3... Qg4xBg2#
  6. *4.P?d3#
  7. *4.P?d4#
  8. *4.B?b2#
  9. *4.R?h8#
  10. *4.R?g7#
  11. *4.RxN#
  12. 4.Qh7xBg7#
  13. 4.Qg4xBg7#
  14. 4.Qg3xBg7#
  15. 4.Qc4-f7#
  16. 4.Rb5-h5#
  17. 4.Rb4-h4#
  18. 4.Rg6-h6#
solutions

23. Magnetic chess problems (ply 7)
In "magnetic chess" (Joao Neto and Claude Chaunier, 1996) when a unit moves, it is magnetised and attracts units of the other color and repels units of the opposite color along the file and rank of the arrival square. Only the "visible" units are attracted or repelled. Kings are not magnetics nor can be attracted or repelled. Castling magnetises the rook. There is no en passant capture but a pawn moved to the first rank retains the two square option.

  1. Find the unique "Magnetic chess" game terminating with 2... P?# (fool's mate)
  2. Find the unique "Magnetic chess" game terminating with 2... QxP# (fool's mate)
  3. Find the unique "Magnetic chess" game terminating with 2... QxQ# (fool's mate)
  4. Find the unique "Magnetic chess" game terminating with 3.o-o# (The Problemist, also 3.R?f1#)
  5. Find the unique "Magnetic chess" game in which white mates on his 3rd move with a bishop (The Problemist)
  6. Find the unique "Magnetic chess" game terminating with 3... Bd6-f8# (The Problemist)
  7. Find the unique "Magnetic chess" game terminating with 3... B?g7# (The Problemist)
  8. Find the unique "Magnetic chess" game terminating with 3... BxB#
  9. Find the unique "Magnetic chess" game terminating with 3... Q?c3#
  10. Find the unique "Magnetic chess" game terminating with 3... Q?g8#
  11. Find the unique "Magnetic chess" game terminating with 3... N?c6#
  12. Find the unique "Magnetic chess" game terminating with 3... Qxd3#
  13. Find the unique "Magnetic chess" game terminating with 3... Qd4-f2#
  14. Find the unique "Magnetic chess" game terminating with 3... Bc4-f7#
  15. Find the unique "Magnetic chess" game terminating with 3... Qg6xPe4#
  16. Find the unique "Magnetic chess" game terminating with 3... Bd5-f7#
  17. Find the unique "Magnetic chess" game terminating with 3... Be6-d7#
  18. Find the unique "Magnetic chess" game terminating with 3... Qd4-d1#
  19. Find the unique "Magnetic chess" game terminating with 3... Qd4xQd1#
  20. Find the unique "Magnetic chess" game terminating with 3... Qd5-e6#
  21. Find the unique "Magnetic chess" game terminating with 3... Ne5-f3#
solutions

24. Air intake chess problems (ply 8)
In "air intake chess" (Alain Brobecker, 2009/02) when a unit leaves a square making a certain movement, it creates an air intake that attracts, if possible, another unit on that square, with the same movement. The attracted unit can be friendly or an opponent and can jump over other units. This can create a chain reaction. For example 1.Nc3 d5 2.Ne4 (>Pc3) Kd7 3.Ra6 Qe8 (>Bd8>Nc8>Rb8) 4.Nc5# is the only game finishing with 4.N?c5#.
En "échecs appel d'air" lorsqu'une pièce quitte une case en effectuant un certain déplacement, elle crée un appel d'air qui attire, si possible, une autre pièce sur cette case avec le même déplacement. La pièce attirée peut être amie ou ennemie et peut sauter au dessus d'autres unités. Cela peut créer une réaction en chaîne. Par exemple 1.Cc3 d5 2.Ce4 (>Pc3) Rd7 3.Ta6 De8 (>Fd8>Cc8>Tb8) 4.Cc5# est l'unique partie se terminant par 4.C?c5#.

  1. Find the unique "air intake chess" game terminating with 2... ?# (unique fool's mate).
  2. Find the unique "air intake chess" game terminating with 3.Q?f5#
  3. Find the unique "air intake chess" game terminating with 4.K?e2#
  4. Find the unique "air intake chess" game terminating with 4.PxQc6#
  5. Find the unique "air intake chess" game terminating with 4.PxQf6#
  6. Find the unique "air intake chess" game terminating with 4.Q?a7#
  7. Find the unique "air intake chess" game terminating with 4.NxQ#
  8. Find the unique "air intake chess" game terminating with 4.Q?d6#
  9. Find the unique "air intake chess" game terminating with 4.RxR#
  10. Find the "air intake chess" games terminating with 4.??h7# (two solutions, or 4.Q?h7# and 4.B?h7#)
  11. Find the unique "air intake chess" game terminating with 4.R?c1#
  12. Find the unique "air intake chess" game terminating with 4.Q?c1#
  13. Find the unique "air intake chess" game terminating with 4.N?a7#
  14. Find the unique "air intake chess" game terminating with 4.QxQe7#
  15. Find the unique "air intake chess" game terminating with 4.BxQ#
  16. Find the unique "air intake chess" game terminating with 4.Qb3xNf7#
  17. Find the unique "air intake chess" game terminating with 4... R?f1#
  18. Find the unique "air intake chess" game terminating with 4... PxBa6#
  19. Find the unique "air intake chess" game terminating with 4... QxPa4#
  20. Find the unique "air intake chess" game terminating with 4... R?g5#
  21. Find the unique "air intake chess" game terminating with 4... QxQf5#
  22. Find the unique "air intake chess" game terminating with 4... PxBf6#
  23. Find the unique "air intake chess" game terminating with 4... NxBd3#
  24. Find the unique "air intake chess" game terminating with 4... N?d2#
  25. Find the unique "air intake chess" game terminating with 4... P?e1=?#
  26. Find the unique "air intake chess" game terminating with 4... PxQc1=R# (also PxQc1=Q#)
  27. Find the unique "air intake chess" game terminating with 4... NxNf4#
  28. Find the unique "air intake chess" game terminating with 4... R?a5#
  29. Find the unique "air intake chess" game terminating with 4... BxBh3#
  30. Find the unique "air intake chess" game terminating with 4... N?h8#
  31. Find the unique "air intake chess" game terminating with 4... Q?h3#
  32. Find the unique "air intake chess" game terminating with 4... P-=?#
  33. Find the unique "air intake chess" game terminating with 4... NxPe2#
  34. Find the unique "air intake chess" game terminating with 4... RxQ#
  35. Find the unique "air intake chess" game terminating with 4... N?e3#
  36. Find the unique "air intake chess" game terminating with 4... NxNc2#
  37. Find the unique "air intake chess" game terminating with 4... PxQe6#
  38. Find the unique "air intake chess" game terminating with 4... Qh3-h4#
  39. Find the unique "air intake chess" game terminating with 4... Rg7xNh7#
  40. Find the unique "air intake chess" game terminating with 4... Ke6-d5#
  41. Find the unique "air intake chess" game terminating with 4... Qh1xPh4#
  42. Find the unique "air intake chess" game terminating with 4... Qb5xRe2#
  43. Find the unique "air intake chess" game terminating with 4... Pg3xPf2#
  44. Find the unique "air intake chess" game terminating with 4... Bc8-h3#
  45. Find the unique "air intake chess" game terminating with 4... Qf3-f2#
  46. Find the unique "air intake chess" game terminating with 4... Ke7-d7#
  47. Find the unique "air intake chess" game terminating with 4... Qb5-a5#
  48. Find the unique "air intake chess" game terminating with 4... Kf6-f5#
solutions

25. Must capture chess problems (ply 9)
In "must capture chess" (mentioned in the Alfonso Manuscript, 1283), a player is obliged to capture if able to do so legally, but may choose between alternatives.

  1. Find the unique "must capture chess" game terminating with 3... QxB#
  2. Find the unique "must capture chess" game terminating with 3... Qb6xPd4#
  3. Find the unique "must capture chess" game terminating with 4.Q?d8#
  4. Find the unique "must capture chess" game terminating with 4.Qb7xQc8#
  5. Find the unique "must capture chess" game terminating with 4.Qd3xPd5#
  6. Find the unique "must capture chess" game terminating with 4... Qc6xBc1#
  7. Find the unique "must capture chess" game terminating with 4... Qg2xPe4#
  8. Find the unique "must capture chess" game terminating with 4... Qb4xPf4#
  9. Find the unique "must capture chess" game terminating with 4... Qc6xPc4#
  10. Find the unique "must capture chess" game terminating with 4... Qd8xPd4#
  11. Find the unique "must capture chess" game terminating with 4... Qg4xQd1#
  12. Find the unique "must capture chess" game terminating with 5.Px#
  13. Find the unique "must capture chess" game terminating with 5.Qa8xBc8#
  14. Find the unique "must capture chess" game terminating with 5.Qb8xPb5#
  15. Find the unique "must capture chess" game terminating with 5.Bg4xNh5#
  16. All other problems with similar stipulation up to ply 8 are: 3... Qf6xPd4#, 3... Qh4xPd4#, 4... Qb5xPc4#, 4... Qa4xPc4#
solutions

26. Logical progressive chess problems (ply 10)
The rules of "logical progressive chess" (Paul Byway, Variant Chess 18, autumn 1995) are as follows:
* White starts with one move; Black plays two consecutive moves, either with the same man or two different men; White then play three moves; and so on, the number of moves increasing by one each time the turn changes.
* A player's turn ends if he gives check, regardless of how many moves he may have made.
* A player may not expose his own king to check at any time during his turn.
* A player whose king is in check must get out of check with the first move of his turn.
* A player who has no legal move or who runs out of legal moves during his turn is stalemated and the game is drawn.
* No pawn two advance and no castling (these rules were invented to speed up orthochess and are superfluous in the fast moving progressive chess).

  1. Find the unique "logical progressive chess" game going 1.? 2.?,? 3.?,?,? 4.Qxg4# (Variant Chess 64, 2010/08)
  2. Find the unique "logical progressive chess" game going 1.? 2.?,? 3.?,?,? 4.?,Qc4# (The Problemist v23n1, 2011/01)
  3. Find the unique "logical progressive chess" game going 1.? 2.?,? 3.?,?,? 4.?,QxNg3# (Die Schwalbe 245, 2010/10)
  4. Find the unique "logical progressive chess" game going 1.? 2.?,? 3.?,?,? 4.?,Qa3-c1# (The Problemist v23n1, 2011/01)
  5. Find the unique "logical progressive chess" game going 1.? 2.?,? 3.?,?,? 4.?,?,Qf6# (Die Schwalbe 245, 2010/10)
  6. Find the unique "logical progressive chess" game going 1.? 2.?,? 3.?,?,? 4.?,?,Qg5-e5# (Die Schwalbe 245, 2010/10)
  7. Find the unique "logical progressive chess" game going 1.? 2.?,? 3.?,?,? 4.?,?,Ng6-f4# (Variant Chess 64, 2010/08)
  8. Find the unique "logical progressive chess" game going 1.? 2.?,? 3.?,?,? 4.?,?,Qh2xRg3# (Variant Chess 64, 2010/08)
  9. Find the unique "logical progressive chess" game going 1.? 2.?,? 3.?,?,? 4.?,?,Qc5-h5# (The Problemist v23n1, 2011/01)
  10. Find the unique "logical progressive chess" game in which black ends the fourth series with Qd7-c6# (Die Schwalbe)
  11. Find the unique "logical progressive chess" game in which black ends the fourth series with Qe5xNg3# (Die Schwalbe)
  12. Find the unique "logical progressive chess" game in which black ends the fourth series with Bh4-f2# (Die Schwalbe)
  13. Find the unique "logical progressive chess" game in which black ends the fourth series with Bb3-d5# (Die Schwalbe)
  14. Find the unique "logical progressive chess" game in which black ends the fourth series with Q?d7# (Die Schwalbe)
  15. All other problems with similar stipulation up to ply 8 are: 4.?,Qc5-b4#; 4.?,Qa3-b4#; 4.?,Qd4-b4#; 4.?,Qc8xQg4#; 4.?,Qa4xQg4#; 4.?,Qe6xQg4#; 4.?,?,Qe6-c4#; 4.?,?,Qc5xBc4#; 4.?,?,Qb4xBc4#; 4.?,?,Qf4xBc4#; 4.?,?,Qa6xBc4#; 4.?,?,Qc5-h5#; 4.?,?,Qg2xNg3#; 4.?,?,Qh3xNg3#; 4.?,?,Qh4xNg3#; 4.?,?,?,Qe7-f6#; 4.?,?,?,Qg5-f6#; 4.?,?,?,Qg1xNg3#; 4.?,?,?,Bh4-e1#; 4.?,?,?,Ba2-d5#;4.?,?,?,Q?c8#
solutions

27. Knightmate chess problems (ply ?)
In "knightmate chess" (Bruce Zimov, 1972), Kings are replaced by royal kNights, while kNights are replaced by non royal Kings.

  1. Find the unique "knightmate chess" game ending with 3.Pa4# (Variant Chess 63, 2010/01)
  2. Find the unique "knightmate chess" game ending with 3... N?e8# (2 solutions, Variant Chess 63, 2010/01)
  3. Find the unique "knightmate chess" game ending with 4.Ba6-e2# (Variant Chess 63, 2010/01)
solutions

28. Upside down chess problems (ply 10)
In "upside down chess" (?), white officers start on 8th rank, white pawns on 7th rank, black officers on 1st rank and black pawns on 2nd rank (FEN: RNBQKBNR/PPPPPPPP/8/8/8/8/pppppppp/rnbqkbnr). The position is a bit cramped but boths sides are only two moves from promotion.

  1. Find the unique "upside down chess" game ending with 3... Ne4xNd6#
  2. Find the unique "upside down chess" game ending with 4... Nh5xRf6#
  3. Find the unique "upside down chess" game ending with 5... Qh2xBh6#
  4. Find the unique "upside down chess" game ending with 5... Ng8xQf6#
  5. All other problems with similar stipulation up to ply 10 are: 4... Nd7xRf6#; 4... Ng4xRf6#
solutions

29. Nightrider chess problems (ply 7)
In "Nightrider chess" (?), the kNights are replaced by Nightriders who can make more than one kNight leap in a given direction. For example 1.Ng1-e5, 1.Ng1xd7, 1.Nb1-d5 and 1.Nb1xe7 are possible on white's first move.

  1. Find the unique "nightrider chess" game ending with 3... Qc6xPe4#;1.Nxd7 Qxd7 2.e4 Qc6 3.Ke2 Qxe4#
  2. Find the unique "nightrider chess" game ending with 3... Qf6-d4#;1.f3 e6 2.Kf2 Qf6 3.Ke3 Qd4#
  3. Find the unique "nightrider chess" game ending with 3... Qf6xPf4#;1.f4 e5 2.Kf2 Qf6 3.Kf3 Qxf4# (BOF, QUASI ORTHODOXE)
  4. Find the unique "nightrider chess" game ending with 4.P?d5#;1.d4 e5 2.Nh4 Ke7 3.Bg5+ Ke6 4.d5#
  5. Find the unique "nightrider chess" game ending with 4.Q?c3#;rnbq1bnr/ppp1pppp/2kp4/3N4/4P3/5Q2/PPPP1PPP/R1B1KBNR
  6. Find the unique "nightrider chess" game ending with 4.N?d5#;rnbq1bnr/ppppp1pp/5k2/5P1Q/8/8/PPPP1PPP/RNB1KBNR
  7. Find the unique "nightrider chess" game ending with 4.N?f4#;rnbk1bnr/pppp1ppp/8/8/8/7N/PPPPQPPP/R1B1KB1R
  8. Find the unique "nightrider chess" game ending with 4.NxPg4#;rnbqkb1r/pppppp1p/8/4N2Q/4P1p1/8/PPPn1PPP/RNB1KB1R
  9. Find the unique "nightrider chess" game ending with 4.NxQb2#;rnb1kb1r/ppp1pppp/8/7N/8/8/PqPQPPPP/RNB1KB1R
  10. Find the unique "nightrider chess" game ending with 4.Qf5-e5#;rnbq1bnr/ppppkppp/8/5Q2/4p3/2P5/PP1PPPPP/RNB1KBNR
  11. Find the unique "nightrider chess" game ending with 4.Qd1-d5# 1.d4 f6 2.d5 Kf7 3.d6 Ke6 4.Qd5#
  12. Find the unique "nightrider chess" game ending with 4.Qe4xPd5#;rnbq1bnr/ppp1pppp/3k4/3p4/4Q3/4P3/PPPP1PPP/RNB1KBNR
  13. Find the unique "nightrider chess" game ending with 4.Qd4-d5#;rnbq1bnr/ppppp1pp/4kp2/8/3Q4/4P3/PPPP1PPP/RNB1KBNR
  14. Find the unique "nightrider chess" game ending with 4.Bh7xNg6#;r1bqkbnr/ppppp1pB/5pn1/8/8/4P3/PPPP1PPP/RNBQK1NR
  15. Find the unique "nightrider chess" game ending with 4.Qd3-b5#;rnbq1bnr/ppp1pppp/2kp4/8/4P3/3Q4/PPPP1PPP/RNB1KBNR
  16. Find the unique "nightrider chess" game ending with 4.Qf4-f5#;rnbq1bnr/ppp1pppp/3pk3/8/4PQ2/8/PPPP1PPP/RNB1KBNR
  17. Find the unique "nightrider chess" game ending with 4.Qd3xPd5#;rnbq1bnr/ppp1pppp/3k4/3p4/4P3/3Q4/PPPP1PPP/RNB1KBNR
  18. Find the unique "nightrider chess" game ending with 4.Qb5xPf5#;rnbq1bnr/ppppp1pp/5k2/1Q3p2/4P3/8/PPPP1PPP/RNB1KBNR
  19. Find the unique "nightrider chess" game ending with 4.Na6xPc7# 1.Nxe7 Nc6 2.Ng3 Qe7 3.Na6 Nd8 4.Nxc7#
  20. Find the unique "nightrider chess" game ending with 4.Qg5-e5#;rnbq1b1r/pppp1ppp/4k3/6Q1/8/8/PPP1PPPP/R1B1KBNR
  21. Find the unique "nightrider chess" game ending with 4.Qe5-d5#;r1b1qbnr/pppkpppp/8/4Q3/8/8/PPPP1PPP/RNB1KB1R
  22. Find the unique "nightrider chess" game ending with 4.Qa4-b5#;rnbq1bnr/ppp1pppp/1k6/8/Q1P5/8/PP1PPPPP/RNB1KB1R
  23. All other problems with similar stipulation up to ply 7 are: 3... Qd4xPe4#; 3... Qg5xPf4#; 3... Qh4xPf4#
solutions

30. Kamikaze chess problems (ply 9)
In "kamikaze chess" (B.G. Laws, 1928) a unit making a capture is removed from the board together with the captured unit. It follows that a king cannot defend itself by capturing an attacker.

  1. Find the unique "kamikaze chess" game ending with 3.Qf3-f7#
  2. Find the unique "kamikaze chess" game ending with *3... B?g4#
  3. Find the unique "kamikaze chess" game ending with 3... Qd6-b4#
  4. Find the unique "kamikaze chess" game ending with 3... Qd6-f4#
  5. Find the unique "kamikaze chess" game ending with 3... Qf6-d4#
  6. Find the unique "kamikaze chess" game ending with 3... Qd5-e4#
  7. Find the unique "kamikaze chess" game ending with 3... Qd4-e4#
  8. Find the unique "kamikaze chess" game ending with *4.P?#
  9. Find the unique "kamikaze chess" game ending with 4.Bd2-g5#
  10. Find the unique "kamikaze chess" game ending with 4.Qd4-c5#
  11. Find the unique "kamikaze chess" game ending with *4... Q?a4#
  12. Find the unique "kamikaze chess" game ending with 4... Qa3-b4#
  13. Find the unique "kamikaze chess" game ending with 4... Qb5-g5#
  14. Find the unique "kamikaze chess" game ending with 4... Qg6-g5#
  15. Find the unique "kamikaze chess" game ending with 4... Qd5-e5#
  16. Find the unique "kamikaze chess" game ending with 4... Qd5-g5#
  17. Find the unique "kamikaze chess" game ending with 4... Qc3-d4#
  18. Find the unique "kamikaze chess" game ending with 4... Qe7-e4#
  19. Find the unique "kamikaze chess" game ending with 4... Re4-e1#
  20. Find the unique "kamikaze chess" game ending with 5.Qd5xPf7# (Die Schwalbe?)
  21. Find the unique "kamikaze chess" game ending with 5.Qa3-a5#
solutions

31. Hoppers (ply 8)
A hopper moves by jumping over the first visible piece of any color (called a hurdle), in a given direction, and landing on the square immediatly behind if this square is empty or occupied by an enemy piece, which is then captured. The hopper moving along the Queen lines is called the Grasshopper (G) (Thomas Rayner Dawson, 1912). The ones moving on the Rook/Bishop lines are called Rookhopper (RH)/Bishoppers (BH). You can put hoppers in the initial position or start with orthodox pieces and allow promotion to this fairy piece afterward in the game.

  1. Find the unique game with orthodox pieces but allowing promotion to Grasshopper and ending with 7... Gb3xb7+. (Alex Levit, Mat Plus Forum 2012/02/29)
  2. When Queens are replaced by Grasshoppers, find the unique game ending in 4.PxN#. (also with GH+RH)
  3. When Queens are replaced by Grasshoppers, find the unique game ending in 4.Gg5xRg8#.
  4. When Queens are replaced by Grasshoppers, find the unique game ending in 4... Pc3xNd2#. (also with GH+RH)
  5. When Queens are replaced by Grasshoppers, find the unique game ending in 4... Pe3xBd2#. (also with GH+RH)
  6. When Queens are replaced by Grasshoppers, find the unique game ending in 4... Nd7-c5# or 4... Nd7-e5#. (also with GH+RH)
  7. When Queens are replaced by Grasshoppers, find the unique game ending in 4... Qh3xRh1#. (also with GH+RH)
  8. When Rooks are replaced by Rookhoppers, find the unique game ending in 4.Rg6xNg8#.
  9. When Rooks are replaced by Rookhoppers, find the unique game ending in 4... P?h5#.
  10. When Bishops are replaced by Bishoppers, find the unique game ending in 4... Q?h5#. (also with RH+BH)
  11. When Queens and Bishops are respectively replaced by Grasshoppers and Bishoppers, find the unique game ending in 4.Pe6xNd7#. (also with GH+RH+BH)
  12. When Queens and Bishops are respectively replaced by Grasshoppers and Bishoppers, find the unique game ending in 4... Qh3xRh1#. (also with GH+RH+BH)
  13. When Queens and Bishops are respectively replaced by Grasshoppers and Bishoppers, find the unique game ending in 4... Qh5xRh1#. (also with GH+RH+BH)
solutions

???. Berkeley chess problems (ply ?)
In "Berkeley chess" (?) every piece, kings excepted, which is no more guarded by a friendly or an unfriendly unit disappears. Thus with the standard setting the rooks, the knights and a;h pawns disappear before the start of the game. Here we consider games starting with the NQRBBRKN setting, were every piece is guarded once.

solutions

???. ??? chess problems (ply ?)

solutions

???. Downloading the program

Solutions:

  1. Orthodox chess
    1. 1.f3 e5 2.Kf2 Qh4+ 3.Ke3 Qd4#
    2. 1.e4 h5 2.Qxh5 Rxh5 3.e5 Rxe5+ 4.Kd1 Re1+
    3. 1.d4 e5 2.Kd2 Qg5+ 3.Kc3 exd4+ 4.Kb3 Qb5#
    4. 1.d4 c6 2.Kd2 Qa5+ 3.Kd3 Qa3+ 4.Kc4 b5#
    5. 1.e3 e6 2.Qg4 Ke7 3.Ne2 Kf6 4.Qxg7+ Kf5 5.Ng3#
    6. 1.d4 e5 2.Qd3 Ke7 3.Bg5+ Ke6 4.Be7 e4 5.Qxe4#
    7. 1.f3 f5 2.Kf2 Kf7 3.Kg3 Qe8 4.Kh4 g5+ 5.Kh5 Kf6#
    8. 1.f4 Nf6 2.Kf2 Nd5 3.Kf3 Nb4 4.Ke4 d5+ 5.Ke5 N4c6#
    9. 1.f4 Nf6 2.Kf2 Nd5 3.Kf3 Nb4 4.Ke4 d5+ 5.Ke5 N8c6#
    10. 1.f4 Nh6 2.Kf2 Nf5 3.Kf3 Nd4+ 4.Ke4 d5+ 5.Ke5 Ndc6#
    11. 1.e4 Nc6 2.Ke2 Ne5 3.Ke3 Ng4+ 4.Kf4 e5+ 5.Kf5 N8h6#
    12. 1.g4 h5 2.Bg2 hxg4 3.Bxb7 Rxh2 4.Nh3 Bxb7 5.OO Rh1#
    13. 1.f4 h5 2.Kf2 Rh6 3.Kg3 Rf6 4.Kh4 e6 5.Kg5 Rh6#
    14. 1.f4 h5 2.Kf2 Rh6 3.Kg3 Rf6 4.Kh4 e6 5.Kg5 Rh6#
    15. 1.f3 e6 2.Kf2 Bc5+ 3.Kg3 Bf2+ 4.Kf4 Qh4+ 5.Ke5 Bd4#
    16. 1.h4 d5 2.h5 Nd7 3.h6 Ndf6 4.hxg7 Kd7 5.Rh6 Ne8 6.gxf8=N#
    17. 6.Bh7#
    18. 6.N?d3#
    19. AUW (Allumwandlung, ie all 4 promotions shown in the same problem):
      1.d3 h5 2.Kd2 h4 3.Kc3 h3 4.Kb4 Rh4+ 5.Ka5 Ra4+ 6.Kxa4 then
      a) 6... hxg2 7.Nf3 g1=N 8.Nd4 Nxe2 9.Nxe2
      b) 6... hxg2 7.Nh3 gxf1=B 8.Rg1 Bxe2 9.Rg4 Bxg4
      c) 6... hxg2 7.h4 gxf1=R 8.Rh3 Rxf2 9.Re3
      d) 6... hxg2 7.h4 gxf1=Q 8.Rh3 Qxe2 9.Re3 Qe1 10.Rxe7+
    20. AUW: 1.b4 a5 2.Bb2 axb4 3.Bxg7 Rxa2 4.Bxh8 Rxa1 5.Bxa1 then
      a) 5... b3 6.Nc3 bxc2 7.Qb1 c1=Q+ 8.Nd1 Qxb1
      b) 5... b3 6.Na3 b2 7.Nc4 bxa1=R 8.Na5 Rxa5
      c) 5... b3 6.e3 bxc2 7.Bd3 cxb1=B 8.Bg6 Bxg6
      d) 5... b3 6.h4 bxc2 7.Rh3 cxd1=N 8.Re3 Nxe3
    21. 1.f3 g5 2.Kf2 g4 3.Kg3 gxf3 4.Kh3 fxe2 5.g3 e1=N 6.Qg4 f5 7.Qg6+ hxg6#
    22. 1.d4 a5 2.d5 Ta6 3.d6 Txd6 4.Sc3 Txd1 5.Sc3xTd1 d6 6.g4 Kd7 7.g5 Kc6 8.g6 Kb5 9.gxh7 Ka4 10.hxg8D Th4 11.Dxf7 Tc4 12.Df7xTc4#.
  2. One sided chess
    1. 1.d4 2.d5 3.d6 4.dxe7 5.Qd6 6.exf8=R#
    2. 1.d4 2.d5 3.d6 4.dxe7 5.Qd6 6.exf8=Q#
    3. 1.d4 2.d5 3.d6 4.dxc7 5.cxb8=Q 6.Qxc8 7.Qxd7#
    4. 1.d4 2.d5 3.d6 4.dxc7 5.cxb8=R 6.Rxb7 7.Rxd7 8.Rxd8#
    5. 1.h4 2.h5 3.h6 4.hxg7 5.Rxh7 6.Rxh8 7.Rxg8 8.Txf8#
    6. 1.d4 2.d5 3.d6 4.dxc7 5.cxb8=R 6.Rxb7 7.Rxd7 8.Rd2 9.Rxd8#
  3. Dissimilar chess. Games i to iv are also mate in orthodox chess, but not game v.
    1. 1.Nc3 e6 2.Ne4 Bd6 3.f3 Bxh2 4.Ng3 Bxg3#
    2. 1.d4 Nf6 2.Bf4 e6 3.Bxc7 Ke7 4.d5 Qe8 5.d6#
    3. 1.Nf3 f6 2.Rg1 Kf7 3.d4 Kg6 4.Qd3+ Kh5 5.g4#
    4. 1.e3 Nc6 2.Bd3 d6 3.Qh5 Bf5 4.Qxf7+ Kd7 5.Bxf5#
    5. 1.Nf3 e5 2.Nxe5 Bb4 3.Ng6 Bxd2+ 4.Qxd2 Nh6 5.Qe3#
    6. Left as an exercise for the reader. ;)
  4. Berolina chess.
    1. 1.Nc3 b5 2.Na4 Kd7 3.b4+ Kc6 4.c5#
    2. 1.f2-e3 d7-f5 2.Kf2 Be6 3.Kf3 Qd7 4.Ke4 Qd5# (the Queen had to come from d7, not d6, to avoid transposition of Black's moves 2 and 3)
    3. 1.f2-e3 d7-f5 2.Kf2 Qd6 3.Kf3 Q:h2 4.e3-f4 Qh2:f4#
  5. Guardian chess. Baseline is NQRBBRKN, then:
    1. 1.f3 c5 2.Kf2 Qd6 3.Ke3 Qd4#
    2. 1.f4 Ng6 2.f5 Kh8 3.fxg6 fxg6 4.Rxf8#
    3. 1.f3 c6 2.Kf2 Qxh2 3.Rg1 Bb6+ 4.Kf1 Qxg1#
    4. Left as an exercise for the reader. ;)
  6. Monochromatic chess.
    1. 1.e4 f5 2.Qh5#
    2. 1.e4 d5 2.exd5 Kd7 3.Bb5#
    3. 1.e4 d5 2.Ba6 Bd7 3.Bxb7 Bc6 4.Bxc6#
    4. 1.a4 e5 2.Ra3 Qh4 3.Rg3 Qxh2 4.f4 Qxg3#
    5. 1.d4 e5 2.Kd2 Qg5+ 3.Kc3 Qxc1 4.Qd3 Qe1# (bicolor play)
    6. 1.e4 e5 2.Bb5 Qf6 3.Bxd7+ Kxd7 4.Qf3 Ke6 5.Qh3# (bicolor play)
    7. 1.c4 f5 2.Qa4 Kf7 3.Qxd7 Kg6 4.Qc6+ Qd6 5.Qe8# (bicolor play)
    8. 1.e4 d5 2.Ba6 Kd7 3.Qg4+ Kc6 4.Qxc8 b5 5.Bb7#
    9. 1.e4 f5 2.Bd3 Kf7 3.Qe2 Ke6 4.exf5++ Kd5 5.Be4# (discovered check)
    10. 1.e4 d5 2.Qe2 Qd6 3.Qa6 b5 4.Bxb5+ Bd7 5.Qc8# (bicolor play, pinned bishop)
    11. 1.d4 g5 2.Kd2 Bg7 3.Ke3 Be5 4.Bd2 Bxh2 5.f4 Bxg1#
    12. 1.f4 h5 2.Kf2 Rh6 3.Kg3 Rf6 4.Kh4 e5 5.Kg5 Rd6# (rook discovered check)
    13. 1.d4 c5 2.Bh6 gxh6 3.Kd2 Qa5+ 4.Ke3 cxd4+ 5.Kf4 Qg5#
    14. 1.f4 e5 2.Kf2 Qf6 3.Kg3 Be7 4.fxe5 d5 5.exd6ep Bxd6# (en passant capture)
    15. 1.h4 e5 2.Rh3 Bc5 3.Rf3 Qe7 4.Rxf7 Qf8 5.Rxd7 Qxf2# (bicolor play)
    16. Left as an exercise for the reader. ;)
    17. Left as an exercise for the reader. ;)
  7. Einstein chess.
    1. 1.e4 f5 2.Qh5=R Kf7 3.Rxh7=Q Kf6 4.Qxf5#
    2. 1.d3 e5 2.Bf4=N Qh4=R 3.Kd2 Rxh2=Q 4.Ke3 Qxf4#
    3. 1.f3 d5 2.Kf2 Bh3=N+ 3.Ke3 f5 4.c4 dxc4=N#
    4. 1.g4 h5 2.Bg2=N hxg4=N 3.Kf1 Rh4=B 4.Qe1=R Bxf2=R#
    5. 1.d3 a5 2.Be3=N a4 3.Kd2 Ra5=B+ 4.b4 axb3=Nep#
    6. 1.e4 d5 2.ed5=N Nc6=P 3.Nf6=P Qd3=R 4.fg7=N+ Kd7 5.Bxd3=R#
    7. 1.d4 d6 2.Bg5=N Kd7 3.e3 Kc6 4.Qg4=R Kd5 5.Re4=B#
    8. 1.d4 c5 2.dc=N f5 3.Qxd7+ Kf7 4.Qxc8 e6 5.Qxe6#
    9. 1.d4 e5 2.Bh6=N Nxh6=B 3.Qd3=R Be3=N 4.Rxe3=Q Ke7 5.Qxe5#
    10. 1.d4 Nh6=P 2.Bxh6=R e5 3.Rxh7=Q exd4=N 4.Qxd4 Ke7 5.Qe4=R#
    11. 1.f4 e5 2.Kf2 Qf6=R 3.Kf3 Rxf4=Q#, 1.f4 e5 2.Kf2 Qh4=R 3.Kf3 Rxf4=Q#, 1.d4 c5 2.dxc5=N e5 3.Qd5=R Ke7 4.Rxe5=Q#, 1.c4 d5 2.cxd5=N Qxd5 3.e4 Qe6=R 4.Ke2 Rxe4=Q#
  8. Frankfurter chess (Rex exclusive).
    1. 1.g4 d6 2.Bg2 Bxg4=P 3.Bxb7=P Qc8 4.Bxc8=Q#
    2. 1.e3 h5 2.Qg4 Rh6 3.Ke2 Rg6 4.Kf3 Rxg4=Q#
    3. Some of those problems already exist in orthodox chess
  9. Chameleon pursuit chess.
    1. 1.g4 Nf6 2.g5 Ne4 3.g6 Ng5(>White) 4.gxf7#
    2. 1.b3 c5 2.Ba3 Qb6 3.Bxc5 Qf6 4.Bb6(>Black) Bxf2#
    3. Some of those problems already exist in orthodox chess
  10. Hypervolage chess.
    1. 1.d3 dxe2 2.Nc3 exd1=R#
    2. 1.c3 cxb2 2.Nc3 bxc1=Q 3.dxc3 Qxc3#
    3. 1.f3 fxe2 2.Nh3 exf1=B 3.Rg1 Ba6#
    4. 1.h3 hxg2 2.e4 gxh1=Q 3.Ke2 Qxe4#
    5. 1.Na3 f6 2.fxe7 Nh6 3.exf8=B Rg8 4.BxNa3#
    6. 1.e3 Nc6 2.Bc4 dxc6 3.Bxf7+ Kd7 4.dxe3#
    7. 1.g3 Na6 2.Bh3 Rb8 3.Rxc8 c6 4.Bxd7#
    8. 1.f3 d6 2.dxc7 Qd6 3.cxb8=Q Qxh2 4.Qg3 QxQg3#
    9. 1.h3 hxg2 2.Rxh7 gxf1=B 3.Rxg7 Bh3 4.Nxh3 Rg1#
    10. 1.f3 g6 2.Kf2 Bh6 3.Nxf3 Nxd2 4.Kg1 Be3#
    11. 1.b3 bxc2 2.Nc3 cxd1=B 3.Rb1 Rxc1 4.Rb1 Bxe2# (switchback, comment of judge: Plusieurs problèmes féeriques, souvent courts, ne présentent à mes yeux pas d'intérêt particulier et sont absents du jugement, même si certains consitituent de joli puzzle comme celui qui demande une partie justificative en 4 coups en échecs hypervolage et se terminant par 4... Bd1xPe2#)
    12. 1.d4 e5 2.Kd2 Qf6 3.Kd3 Qa6 4.Qxa7 Qxd4#
    13. 1.c3 cxb2 2.Nc3 bxc1=Q 3.dxc3 Qa3 4.c4 Qa5#
    14. 1.d3 dxc2 2.Qd6 Qa3 3.Be3 cxb1=Q+ 4.Kd2 Qaxb2#
    15. Left as an exercise for the reader. ;)
  11. Andernach chess.
    1. 1.e3 d5 2.Ke2 Qd6 3.Kd3 Qxh2(>White) 4.Qxc7(>Black) Qc4#
    2. 1.f3 c5 2.Kf2 Qa5 3.Ke3 Qxd2(>White) 4.Qxd7(>Black) Qd4#
    3. Left as an exercise for the reader. ;)
  12. Anti-Andernach.
    1. 1.e3 Nh6 2.Bd3 Bg6 3.Bxf7#
    2. 1.f3 fxg2 2.Nh3 gxf1=N 3.Rg1 Nxh2#
    3. 1.Nc3 Nxa2 2.Rb1 Nxc1 3.Qxc1 Rxc1#
    4. 1.c3 cxb2 2.Nc3 bxc1=Q 3.dxc3 Qxc3#
    5. 1.b4 f6 2.fxe7 Nh6 3.exf8=B Rg8 4.Bxb4#
    6. 1.d3 dxe2 2.Kd2 e1 3.Bc4 Be6 4.Qf3 dxe6# (pawn on first rank)
    7. 1.g3 gxh2 2.f3 hxf1=N 3.Rh2 Rf2 4.e3 Bxf2#
    8. 1.g3 gxh2 2.Bg2 hxg1=N 3.Rxh7 Bf3 4.Rh1 Nxf3# (switchback, double checkmate)
    9. 1.h3 hxg2 2.Rxh7 gxf1=N 3.Rh1 Rh2 4.Nh3 Nxh2# (switchback, play on both sides)
    10. Left as an exercise for the reader. ;)
  13. Cardiac chess.
    1. 1.d4 e5 2.Qd3 exd4 3.Qe4+
    2. 1.c3 d6 2.Qb3 Be6 3.Kd1 Bxb3+
    3. 1.e4 h5 2.Qxh5 Rxh5 3.e5 Rxe5+
    4. 1.d3 g5 2.Kd2 Bh6 3.Kc3 Bg7+ (pg5 acts as a shield)
    5. 1.d4 c5 2.dxc5 e5 3.Qd6 e4 4.Qe5+
    6. 1.d4 e5 2.dxe5 d6 3.Qxd6 Be6 4.Qxe6+
    7. 1.d4 e5 2.Qd3 Ne7 3.Qe4 exd4 4.Qxe7+
    8. Left as an exercise for the reader. ;)
  14. Grid chess.
    1. 1.e4 d6 2.Qh5 Kd7 3.Bb5+ Ke6 4.Qd5#
    2. 1.e4 d6 2.Qf3 Kd7 3.Bb5+ Ke6 4.Qb3#
    3. 1.e4 d5 2.Qh5 Bg4 3.Qxd5 Qxd5 4.Nh3 Qxe4#
    4. 1.d3 Nf6 2.Kd2 Ne4+ 3.Ke3 Nd6 4.Nd2 Nf5#
    5. 1.d3 e5 2.Kd2 Ba3 3.Ke3 Bxb2 4.Nd2 Bd4#
    6. 1.d3 c6 2.Kd2 Qa5+ 3.Ke3 Qf5 4.Nd2 Qc5#
    7. In all other problems the white moves are 1.d3 2.Kd2 3.Ke3 4.Nd2.
  15. Displaced grid chess.
    1. 1.e4 f5 2.Qh5#
    2. 1.e4 e5 2.Qh5 Ke7 3.Qxe5#
    3. 1.d4 e5 2.Bg5 Qxg5 3.Qc1 Qxc1#
    4. 1.Nc3 c5 2.Nd5 Qb6 3.Nc7#
    5. 1.d4 e5 2.Qd3 Ke7 3.Qg6 Kf6 4.Bg5# (grid prevents check from Q)
    6. 1.d4 e5 2.Bd2 Qg5 3.Bb4 Qc1 4.Na3 Bxb4# (pin)
    7. 1.d4 e5 2.Bg5 Qxg5 3.Nc3 Qg3 4.Qb1 Qxc3#
    8. 1.e4 f5 2.exf5 g5 3.fxg6ep h5 4.Qxh5 Rh7 5.gxh7# (ep capture + discovered mate)
    9. 1.e4 e5 2.Qg4 Ke7 3.Qe6 f5 4.exf5 Nh6 5.f6#
    10. 1.h4 g5 2.hxg5 e5 3.Rh6 Ke7 4.Re6 Nf6 5.gxf6#
    11. 1.d4 Nf6 2.Bg5 Ne4 3.Bf6 exf6 4.Qd3 Ke7 5.Qxe4#
    12. 1.h4 g5 2.hxg5 Nf6 3.gxf6 exf6 4.Rh3 Ke7 5.Re3#
    13. 1.e4 f5 2.exf5 e5 3.fxe6ep Qf6 4.Qf3 Qf7 5.Qxf7# (ep capture)
    14. 1.Nc3 e5 2.Nd5 Qf6 3.Ne7 Nc6 4.Nxg8 Ne7 5.Nxf6#
    15. Left as an exercise for the reader. ;)
  16. Handicap chess.
    1. White gave WPe2 then 1.Bd3 f6 2.Bxh7 g6 3.Bxg6#
    2. White gave WPe2 then 1.Qg4 e5 2.Qxg7 Ke7 3.Qxe5#
    3. White gave WPd2 then 1.Qd4 e5 2.Kd2 Qh4 3.Kd3 Qxd4#
    4. White gave WPd2 then 1.Kd2 c5 2.Kc3 Qa5+ 3.Kb3 Qb4#
    5. White gave WPb2 then 1.e4 e6 2.Qh5 Ke7 3.Ba3+ Kf6 4.e5#
    6. White gave WPd2 then 1.d4 f6 2.Bf4 Kf7 3.Qh5+ Ke6 4.d5#
    7. White gave WPe2 then 1.Bd3 e5 2.Qe2 e4 3.Bxe4 d6 4.Bc6#
    8. White gave WPh2 then 1.e4 f6 2.Qf3 Kf7 3.Bc4+ Kg6 4.Qg3#
    9. White gave WPb2 then 1.e4 e5 2.Qg4 Ke7 3.Ba3+ Kf6 4.Qf5#
    10. White gave WPc2 then 1.Qb3 d5 2.Qxb7 Kd7 3.Qxa8 Qe8 4.Qxd5#
    11. White gave WPd2 then 1.a4 f6 2.Ra3 Kf7 3.Qd5+ Kg6 4.Rg3#
    12. White gave WPd2 then 1.h4 f6 2.Rh3 Kf7 3.Qd5+ Kg6 4.Rg3#
    13. White gave WPd2 then 1.Qd5 h6 2.Bxh6 f6 3.Bxg7 Rh5 4.Qxh5#
    14. White gave WPd2 then 1.Qd4 e6 2.Qxg7 Ke7 3.Qxg8 Kf6 4.Qg5#
    15. White gave WPe2 then 1.Qf3 d6 2.Qxb7 Kd7 3.Qxb8 Kc6 4.Qb5#
    16. White gave WPe2 then 1.Qg4 Nf6 2.Qxg7 Nh5 3.Qe5 f6 4.Qxh5#
    17. White gave WPe2 then 1.Ba6 d6 2.Qe2 Kd7 3.Qf1 Kc6 4.Qb5#
  17. Fool's chess. Baseline is NBQRRKBN, then:
    1. 1.e4 c5 2.Re2 Dc6 3.Tf1 Dxe4#
    2. 1.c4 f6 2.Fg6 Fxc4 3.Dxc4 Cf7 4.Dxf7#
    3. 1.e4 d5 2.exd5 Qg4 3.Rxe7 Qxd1+ 4.Re1 Rxe1# (switchback)
    4. 1.e4 d5 2.Ke2 Rd6 3.Rf1 Re6 4.Ke1 Rxe4# (wK and wR exchange place)
    5. 1.e4 f5 2.exf5 e6 3.Rxe6 Bxe6 4.Ke1 Bc4# (battery)
    6. 1.c3 b6 2.Bf5 Qa6 3.Bh3 Qd3 4.g4 Qxh3#
    7. 1.f3 c5 2.Bf2 Qc6 3.Kg1 Qh6 4.Rf1 Qxh2#
    8. 1.Nb3 f6 2.Nc5 Be6 3.Nxd7+ Bxd7 4.g3 Bh3#
    9. Left as an exercise for the reader. ;)
  18. Provocative chess.
    1. 1.Nh3 Nc6 2.Nf4 Ne5 3.Nd3 Nxd3#
    2. 1.c4 e5 2.c5 Qf6 3.c6 Se7 4.c×b7 Qa6 5.b×c8=R#
    3. If the mate is a discovered one, we have WQa1 and BKh8, but whatever the rest of the setup, black would easily shield from such a checkmate.
      So the WNe6 gives direct mate and 3 moves are needed to bring the BR on e6 (with only two moves we would have e7-e5 and Re8-e6, but the BK would then be on f8 with e8 and e7 free). So we had at the beginning Kf and Qc, and the BPf and BPc have not moved. The WN must be on an observed dark square before 4.NxRe6#. If it is on c5, d4, f4 or g5 the square is guarded by a B or P. But with the BQc8 and BPc7 unmoved, only a BBh8 could fit (again, BPe7 is also unmoved). But 1... g7-g5 2... Rg8-g6 3... Rg6-e6 gives again too much room to BK.
      So the WN comes from c7 or g7 and has captured a BP there (BPc7 is unmoved and for 1... g7-g5 see above). If WN comes from c7 we have BBa8+BRb8 to observe d5 to allow WNd5xc7, and this after 1... b7-b5 2... Rb8-b6. But then the BNs would be on d and e squares and 4... Nc7xe6 wouldn't mate.
      So the WN comes from g7 and went through the f5 square, observed by the BQc8. So the Rs were on d and e squares. Last the Ns were on a and h so that the WNh1 could go on f5.
      So the setup was NBQRRKBN and we have: 1.Ng3 d5 2.Nf5 Rd6 3.Nxg7 Re6 4.Nxe6#
    4. B has only played with his N. At the end of the game the BN attacks g1 and f2. The WK is on g1. Then the WR can't come from h1 or f1, since this would give squares to the WK. Since the WR doesn't come from h1, then W played a P then two R moves, so the K are on the g-file at the beginning and Q on the b-file.
      Retro play of the BN is:
            Ng5     Nd8
     /   \   /
  Nh3     Ne6
     \   /   \
      Nf4      Nf8
         \   /
          N4
             \
              Nh8
      But W must oberve f4 or/and g5 to have NxRh3, and this can't be with 1.f4 since the WR can't come from f. So it's WBc1 which observes f4 and g5 after 1.d4, so the B ares on c and f-files at the beginning, and R on d and e-files.
      So the setup was NQBRRNKN and we have: 1.d4 Ng6 2.Rd3 Nf4 3.Rh3 Nxf3#
  19. Patrol chess.
    1. 1.e3 d5 2.Qf3 Kd7 3.Qxd5+ Qe8 4.Bc4#
    2. 1.c3 d5 2.Qb3 Kd7 3.Qxd5+ Qe8 4.c4#
    3. Left as an exercise for the reader. ;)
  20. Antipatrol chess.
    2. Left as an exercise for the reader. ;)
  21. Banana skin chess.
    1. 1.e6 fxe6 2.Qh5#
    2. 1.d6 cxd6 2.Na3 Qa5#
    3. 1.e6 f3 2.Qe2 fxg2 3.Qh5#
    4. 1.e6 dxe6 2.Qh5 Qd3 3.Kd1 Qxf1#
    5. 1.Nf3 a3 2.Ne5 Ra4 3.e4 Rxe4#
    6. 1.f6 exf6 2.Nc3 Ke7 3.d6 Ke6 4.Qd5#
    7. 1.g6 Nc6 2.c5 d3 3.gxf7+ Kd7 4.Bh3#
    8. 1.d6 b3 2.dxc7 Ba6 3.c8=Q Nc6 4.Qdxd7#
    9. 1.e6 c3 2.Qh5 Qa5 3.exf7+ Kd8 4.Qxa5#
    10. 1.e6 fxe6 2.Nc3 Kf7 3.Qh5+ Kf6 4.Ne4#
    11. 1.d6 Nh6 2.Qd5 Nf5 3.dxe7 Kxe7 4.Qe5#
    12. 1.f6 exf6 2.Kf2 f3 3.exf3 Nh6 4.Qe2# (hard)
    13. 1.c6 Na6 2.cxd7 Bxd7 3.Qa4 Bb5 4.Qxb5#
    14. 1.c6 e3 2.dxe3 Qh4 3.e7 dxc6 4.Qd8#
    15. 1.d6 Nc6 2.Qd5 Ne5 3.dxe7 Kxe7 4.Qxe5#
    16. 1.d6 Nh6 2.dxe7 Qxe7 3.Bg5 Qxe2+ 4.Qxe2#
    17. 1.c6 Nxc6 2.Qa4 Nb4 3.Qxb4 d3 4.Qa4# (switchback)
    18. 1.c6 b3 2.Qc2 Nxc6 3.Qg6 d3 4.Nxc6#
    19. Left as an exercise for the reader. ;)
  22. Baseline chess.
    1. qrbnnbrk/pppppppp/8/8/8/8/PPPPPPPP/QRBNNBRK then 1.h4 a5 2.h5 Qa6 3.h6 Qxh6#
    2. QRBNNBRK then 1.h4 b5 2.h5 Rb6 3.h6 Rxh6#
    3. QRBNNBRK then 1.h4 g5 2.h5 Rg6 3.h6 Rxh6#
    4. bnqrrknb/pppppppp/8/8/8/8/PPPPPPPP/BNQRRKNB then 1.g3 d6 2.Bxb7 Qh3+ 3.Bg2 Qxg2#
    5. BNQRRKNB then 1.g4 d6 2.Bxb7 Qxg4 3.Bg2 Qxg2#
    6. QRBNNBRK then 1.g4 h5 2.g5 Kh7 3.g6+ Kh6 4.d3#
    7. QRBNNBRK then 1.g4 h5 2.g5 Kh7 3.g6+ Kh6 4.d4#
    8. *4.B?b2#
    9. *4.R?h8#
    10. *4.R?g7#
    11. *4.RxN#
    12. BNQRRKNB then 1.c4 g5 2.Qc2 Bxb2 3.Qxh7 Bg7 4.Qxg7#
    13. BNQRRKNB then 1.d3 g5 2.Qxg5 Bxb2 3.Qg4 Bg7 4.Qxg7#
    14. BNQRRKNB then 1.d3 g5 2.Qxg5 Bxb2 3.Qg3 Bg7 4.Qxg7#
    15. rbqnnkbr/pppppppp/8/8/8/8/PPPPPPPP/RBQNNKBR then 1.c4 f6 2.Bg6 Bxc4 3.Qxc4 Nc6 4.Qf7#
    16. QRBNNBRK then 1.b4 a5 2.bxa5 h5 3.Rb5 h4 4.Rh5#
    17. QRBNNBRK then 1.b4 h5 2.b5 h4 3.Rb4 h3 4.Rh4#
    18. QRBNNBRK then 1.g4 h5 2.gxh5 g6 3.Rxg6 Ng7 4.Rh6#
    19. Left as an exercise for the reader. ;)
  23. Magnetic chess.
    1. 1.e4 (e7>e5) Qh4 (e4>g4, h7>h6) 2.Ne2(e5>e3) exf2# (if 2... Qxf2 3.Nf4)
    2. 1.e4 (e7>e5) Qh4 (e4>g4, h7>h6) 2.Be2(e5>e3) Qxf2# (if 2... exf2 3.Kf1)
    3. 1.d3 (d7>d4) Bg4 (d4>a4, g2>g3) 2.e3 (d3>a3, g3>h3) Qxd1#
    4. 1.g4 (g7>g5) f5 (f2>f4;g5>h5) 2.Bh3 (h5>h6) fxg4 (Ng1>g3) 3.o-o (f4>f7)#
    5. 1.d4 (d7>d5) g5 (g2>g4;d5>a5) 2.Bf4 (f7>f5;g4>h4;d4>a4) gxh4 (h2>h3;Bf4>g4) 3.Bh5 (h7>h6;f5>g5)#
    6. 1.c3 (c7>c4) f5 (f2>f4) 2.e4 (e7>e5;c4>d4;f4>h4) Bd6 (d4>d3) 3.c4 (Bc8>c5;e4>g4) Bf8 (f5>f7)# (Switchback) rn1qkbnr/pp1p2pp/8/2b1p3/2P3PP/3p4/PP1P1pPP/RNBQKBNR
    7. 1.e3 (e7>e4) Ne7 2.g4 (g7>g5;e4>f4) Nf5 (f4>f3;g5>h5) 3.gxh5 (h7>h6;Nf5>g5) Bg7 (Ng5>g2;f7>e7)# (4.Bxg2 fails due to Bg7>g3 and f2>e2) rnbqk2r/ppppp1b1/7p/7P/8/4Pp2/PPPP1PnP/RNBQKBNR
    8. 1.d3 Qd5 2.Bg5 Bh6 3.Kd2 Bxg5#
    9. 1.d3 Qd6 2.Nc3 Qb4 3.Kd2 Qxc3#
    10. 1.d3 Nh6 2.f3 Qd5+ 3.Kf2 Qg8#
    11. 1.c3 Qe7 2.d3 Qc5 3.Kd2 Nc6#
    12. 1.d3 Be6 2.Ke2 Bc4 3.Qe1 Qxd3#
    13. 1.c3 Qc7 2.f4 Qxf4 3.c4 Qf2# (fake switchback)
    14. 1.c3 Qb6 2.f3 c3 3.Nxc3 Bf7# (fake switchback)
    15. 1.c4 Qb6 2.e4 Qg6 3.Ke2 Qxe4#
    16. 1.d3 Bd7 2.f4 e3 3.d4 Bf7#
    17. 1.d3 Be6 2.e3 Qd5+ 3.Ke2 Bd7#
    18. 1.d3 Bg4 2.e3 Qd4 3.Qxh7 (else the BQ can be deviated) Qd1#
    19. 1.d3 Bg4 2.h4 (so that Bg4 doesn't move anymore) Qd4 3.e3 Qxd1#
    20. 1.d3 Bg4 2.Kd2 Bxe2 3.d4 Qe6#
    21. 1.e3 Ne6 2.Ne2 Ne5 3.g3 Nf3# (fake switchback, WPc & d swapped)
  24. Air intake chess.
    1. 1.e3 (>Ke2) d6 (>Qd7) 2.Kf3 (>Qe2) Qg4#
    2. 1.e4 Nf6 2.Qh5 Ng4 (>Kf6) 3.Qf5#
    3. 1.e3(>Ke2) e6 (>Ke7) 2.e4 (>Ke3) Kd6 (>Be7) 3.Qf3 Ke5 (>Pd6>Nc7) 4.Ke2 (>Pe3>Ke4>Pe5>Be6)#
    4. 1.e4 d5 2.Qf3 Qd7 3.exd5 (>>Qe4>Pf3>Rg2) Qc6 (>>Ke7) 4.dxc6 (>Qe5>Pe4>Rf3)#
    5. 1.d4 e5 2.dxe5 Qf6 3.Qd4 Ke7 4.exf6 (>Qe5)#
    6. 1.Nc3 b5 2.Nxb5 (>Qc3) e6 (>Ke7) 3.Qxc7 Nc6 4.Qxa7 (>Kc7>Pe7)#
    7. 1.Nc3 c5 2.Nb5 (>Qc3) Qc7 3.Qf6 e5 4.Nxc7#
    8. 1.Nf3 e6 (>Ke7) 2.Nh4 (>Pf3>Nd2) Qe8 (>Bd8>Nc8>Ra8) 3.Ne4 c6 (>Nc7) 4.Qd6#
    9. 1.Nf3 g6 (>Ng7) 2.Nd4 (>Pf3) Ne6 3.Rxh7 Nxd4 (>Be6) 4.Rxh8#
    10. 1.c3 (>Bc2) Nf6 2.Bb3 (>Qc2) Ng5 (>Kf6) 3.Qe4 Ne5 4.Qxh7 (>Ne4)# & 1.c3 (>Bc2) Nf6 2.Be4 Ng5 (>Kf6) 3.Qb3 Ne5 4.Bxh7 (>Ne4)#
    11. 1.c3 (>Bc2) e6 (>Ke7) 2.c4 (>Bc3) Kd6 (>Be7) 3.Be5 (>Rc3)+ Kc5 (>Bd6) 4.Rc1 (>Kc3>Pc5)# (quintuple check)
    12. 1.c3 (>Bc2) e6 (>Ke7) 2.Bb3 (>Qc2) Kd6 (>Be7) 3.c4 (>Qc3) Kc5 (>Bd6) 4.Qc1 (>Kc3>Pc5)# (quadruple check)
    13. 1.c4 e6 (>Ke7) 2.Nc3 Kd6 (>Be7) 3.Nb5 (>Qc3)+ Kc6 (>Pd6) 4.Nxa7 (>Qb5)#
    14. 1.d3 (>Qd2) e5 2.Qb4 Qe7 3.Bg5 Kd8 (>Be8>Nf8>Rg8) 4.Qxe7#
    15. 1.d3 (>Qd2) e5 2.Qf4 Qg5 3.Qxf7 (>Bf4)+ Kd8 (>Be8>Nf8>Rg8) 4.Bxg5#
    16. 1.c3 (>Bc2) f6 (>Bf7) 2.Bg6 Be6 (>Nf7) 3.Qb3 Bh3 4.Qxf7#
    17. 1.c3 (>Bc2) Nf6 2.Bxh7 Nd5 (>Bf6) 3.Bd4 (>Rf6) Ne3 (>Pd5) 4.Bb6 (>Pd4) Rxf1#
    18. 1.e3 (>Ke2) d6 (>Qd7) 2.e4 (>Ke3) Qh3+ 3.e5 (>Ke4) dxe5 (>Pd6>Nc7) 4.Ba6 bxa6 (>Bb7)#
    19. 1.e3 (>Ke2) d6 (>Qd7) 2.Kd3 (>Be2) Qb5+ 3.Kc3 (>Pd3) Nc6 4.a4 Qxa4 (>Nb5)#
    20. 1.e3 (>Ke2) f6 (>Bf7) 2.e4 (>Ke3) f5 (>Bf6) 3.Kf4 (>Pe3>Bd2) Be5(>Pf6>Rg7)+ 4.Kxf5 Rg5#
    21. 1.e3 (>Ke2) h5 2.Kf3 (>Qe2) h4 3.Kg4 (>Qf3) d6(>Qd7)+ 4.Qf5 (>Bf3) Qxf5#
    22. 1.f3 (>Bf2) d6 (>Qd7) 2.Bg3 (>Kf2) Qa4 3.Bh4 (>Kg3) Qd4 4.Bf6 gxf6(>Rg7)#
    23. 1.Nc3 Nc6 2.Na4 (>Pc3>Ne2) Nb4 (>Qc6) 3.c4 (>Pc3Bc2) Qxa4 (>Kc6) 4.Bd3 Nxd3#
    24. 1.Nc3 b6 (>Nb7) 2.Nb5 (>Qc3) Nc5 3.Qa5 (>Kc3) Nb3 (>Pc5) 4.Kc4 (>Pc3>Bc2) Nxd2#
    25. 1.Nc3 d5 2.Nb1 (>Pc3>Pd5) Bb4 3.d3 (>Qd2) cxd2 (>Bc3)+ 4.Kd1 (>Be1>Nf1>Rg1) d2xe1=Q (>Bd2)# (switchback)
    26. 1.Nc3 d5 2.Nb1 (>Pc3>Pd5) c3xb2 3.c3 (>Bc2) Ba3 4.Qc1 (>Kd1>Be1>Nf1>Rg1) bxc1=Q (>Bb2)#
    27. 1.Nc3 f6 (>Bf7) 2.Na4 (>Pc3>Ne2) Be6 (>Nf7) 3.Nf4 Bd5 (>Ne6) 4.Ke2 Nxf4 (>Qe6)#
    28. 1.Nf3 Nc6 2.Ng5 (>Kf3) Ne5 (>Pc6)+ 3.Nxh7 (>Kg5) Ng6 4.g4 Ra5#
    29. 1.Nf3 Nc6 2.g3 Ne5 (>Pc6) 3.Bh3 Nxf3 (>Pe5)+ 4.Kf1 Bxh3#
    30. 1.Nf3 d6 (>Qd7) 2.Ng5 (>Kf3) Kd8 3.Nxh7 f6+ 4.Kg6 Nh8#
    31. 1.Nf3 d6 (>Qd7) 2.Ng5 (>Kf3) Qf5+ 3.Kg3 Nd7 4.Nf3 (>Pg5) Qh3 (>Nf5)#
    32. 1.Nf3 e5 2.Ng1 (>Pf3>Pe5) Qh4 3.g3 (>Ng2) fxg2 4.f4 g1=N (>Pg2)# (switchback)
    33. 1.Nf3 g6 (>Ng7) 2.Ng5 (>Kf3) Ne6 3.Kg3 Nf4 (>Qe6) 4.Nf3 (>Pg5) Nxe2 (>Pf4>Rg6)#
    34. 1.c3 (>Bc2) Nc6 2.Bb3 (>Qc2) Rb8 3.Qc1 (>Pc2) Nd4 (>Rc6) 4.Ba4 (>Pb3) Rxc1#
    35. 1.c3 (>Bc2) g6 (>Ng7) 2.Qc1 (>Kd1>Be1>Nf1>Rg1) Nf5 3.Bb3 (>Kc2) Bg7 4.Bc4 (>Pb3) Ne3 (>Bf5)#
    36. 1.d3 (>Qd2) Nc6 2.Qf4 Nb4 (>Qc6) 3.Qe4 Qxc2 4.Qf5 (>Pe4>Qd3>Nc2) Nxc2#
    37. 1.d3 (>Qd2) c6 (>Bc7) 2.Qc3 (>Kd2) Bg3 3.Qb3 (>Pc3) Bxf2 4.Qe6 dxe6#
    38. 1.Nf3 d6 (>Qd7) 2.Ng5 (>Kf3) Qh3+ 3.Nxh7 Rxh7 4.Rg1 (to avoid 5.Rh2-h1) Qh4#
    39. 1.Nf3 d6 (>Qd7) 2.Ng5 (>Kf3) Kd8 (>Be8>Nf8>Rg8) 3.Nxh7 (>Kg5) g6 (>Rg7) 4.Kh6 Rxh7 (>Pg7>Pf7>Qe7>Pd7>Pc7>Pb7)# (7 pieces move)
    40. 1.Nf3 d6 (>Qd7) 2.Ng5 (>Kf3) Qe6 (>Bd7) 3.Nxh7 (>Kg5) Qe4 (>Ke6) 4.Nxf8+ Kd5 (>Pe6>Nf7)# (cross checks)
    41. 1.f3 (>Bf2) e5 2.Bg3 (>Kf2) Qh4 3.Bf4 (>Pg3) Qxh1 (>Ph4) 4.gxh4 (>Kg3) Qxh4#
    42. 1.Nc3 d6 (>Qd7) 2.Rb1 Qb5 3.Ra1 (>Bb1>Qc1>Kd1>Be1>Nf1>Rg1) Bg4 4.Na4 (>Pc3>Re2) Qxe2# (switchback, 7 pieces move)
    43. 1.Nc3 g5 2.Na4 (>Pc3>Ne2) g4 3.Nb6 g3 4.Na4 (>Bb6) gxf2# (switchback)
    44. 1.Nf3 Nc6 2.g3 Ne5 (>Pc6) 3.Rg1 Nxf3 (>Pe5)+ 4.Rh1 (>Bg1>Kf1>Qe1>Bd1>Nc1>Rb1) Bh3# (switchback, 7 pieces move)
    45. 1.f4 c6 (>Bc7) 2.f5 Bb6 (>Qc7) 3.Nf3 Qe5 4.Ng1 (>Qf3>Pe5) Qf2# (switchback)
    46. 1.e3 (>Ke2) d6 (>Qd7) 2.Kf3 (>Qe2) Qf5+ 3.Kg3 (>Pf3) e6 (>Ke7) 4.Kh4 (>Pg3) Kd7 (>Pe7>Pf7>Pg7)#
    47. 1.e3 (>Ke2) c5 2.e4 (>Ke3) Qb6 3.e5 (>Ke4) Qb5 (>Pb6>Nb7) 4.Kd5 Qa5 (>Pb5>Kc5>Pd5)#
    48. 1.e3 (>Ke2) e5 2.Kd3 (>Be2) Ke7 3.Ke4 (>Pd3>Nc2) Kf6 (>Qe7) 4.Kd5 Kf5 (>Pf6>Bf7)# (75% of kings moves)
  25. Must capture chess.
    1. 1.d4 e6 2.Qd3 Qg5 3.Qxh7 Qxc1#
    2. 1.d4 c6 2.Kd2 Qb6 3.Qe1 Qxd4#
    3. 1.d4 d6 2.Bg5 e5 3.dxe5 dxe5 4.Qxd8#
    4. 1.e3 b6 2.Qf3 Bb7 3.Qxb7 Qc8 4.Qxc8#
    5. 1.e3 d5 2.Qe2 Kd7 3.Qd3 Qe8 4.Qxd5#
    6. 1.c4 d5 2.cxd5 Qxd5 3.Qa4+ Qc6 4.Qxa7 Qxc1#
    7. 1.e4 e5 2.Ke2 Qg5 3.Nf3 Qxg2 4.Nxe5 Qxe4#
    8. 1.d3 e5 2.Kd2 Qe7 3.Ke3 Qb4 4.f4 Qxf4#
    9. 1.e3 d5 2.Ke2 Qd7 3.Kd3 Qc6 4.c4 Qxc4#
    10. 1.d4 d5 2.Kd2 Bf5 3.c4 dxc4 4.Qe1 Qxd4#
    11. 1.e4 d6 2.Bd3 Qd7 3.Ke2 Qg4+ 4.Kf1 Qxd1#
    12. 1.e4 f5 2.exf5 g6 3.fxg6 h6 4.Qh5 Rh7 5.gxh7#
    13. 1.e3 d6 2.Qf3 b5 3.Qxa8 Na6 4.Bxb5+ Qd7 5.Qxc8#
    14. 1.e3 d6 2.Qf3 b5 3.Qxa8 Kd7 4.Qxb8 Kc6 5.Qxb5#
    15. 1.g4 f5 2.gxf5 Nf6 3.Bh3 Nh5 4.Bg4 g5 5.Bxh5#
    16. Left as an exercise for the reader. ;)
  26. Logical progressive chess.
    1. 1.e3 2.d6,Qd7 3.Qg4,Ke2,Kf3 4.Qxg4#
    2. 1.e3 2.c6,Qc7 3.Bb5,Ke2,Kd3 4.cxb5,Qc4#
    3. 1.Nc3 2.e6,Qh4 3.Ne4,Ng3,f3 4.Qxh2, Qxg3#
    4. 1.c3 2.e6,Qe7 3.Qa4,b3,Ba3 4.Qxa3,Qc1#
    5. 1.e3 2.d6,d5 3.Ke2,Kd3,Kd4 4.Bf5,e6,Qf6#
    6. 1.d3 2.d6,Bg4 3.Kd2,Ke3,Ke4 4.e6,Qg5,Qe5#
    7. 1.f3 2.e6,Ne7 3.Kf2,Kg3,Kh3 4.Ng6,Qg5,Nf4#
    8. 1.a3 2.e6,Bxa3 3.Rxa3,Rg3,f3 4.Qh4,Qxh2,Qxg3#
    9. 1.f3 2.e6,Qe7 3.Kf2,Kg3,Kh3 4.Qc5,Bd6,Qh5#
    10. 1.d3 2.e6,e5 3.Kd2,Ke3,Ke4 4.Bc5,d6,Qd7,Qc6#
    11. 1.Nc3 2.e6,Qh4 3.Ne4,Ng3,f3 4.Qxh2,Qh5,Qe5,Qxg3#
    12. 1.f3 2.e6,Be7 3.Kf2,Kg3,Kh3 4.Bh4,Qg5,Qh5,Bf2#
    13. 1.d3 2.d6,Be6 3.Kd2,Ke3,Kf3 4.Bb3,e6,Qg5,Bd5#
    14. 1.f3 2.d6,Bh3 3.Kf2,Kg3,Kxh3 4.h6,h5,h4,Qd7#
    15. Left as an exercise for the reader. ;)
  27. Knightmate chess.
    1. 1.d4 Nd6 2.Bf4+ Nb5 3.a4#
    2. 1.Nd3 Nd6 2.Nb4 e6 3.d3 Ne8# and 1.Nf3 Nf6 2.Nh4 e6 3.f3 Ne8# (can be separated in 3... Nd6-e8# and 3... Nf6-e8# which both have only one solution.)
    3. 1.e3 Nf6 2.Qh5 Nxh5 3.Ba6 f6 4.Be2#
    4. Left as an exercise for the reader. ;)
  28. Upside down chess.
    1. 1.Nh6 Nc3 2.Nf5 Ne4 3.Nd6 Nxd6#
    2. 1.Nh6 Nh3 2.g8=R Nf4 3.Rg6 Nh5 4.Rf6 Nxf6#
    3. 1.Nf6 Nf3 2.g8=B Rg1 3.Bh6 h1=Q 4.Kf8 Qh2 5.Qe8 Qxh6#
    4. 1.Nc6 Nc3 2.b8=Q Nd5 3.Qxb2 Nxe7 4.Qf6 Nxg8 5.Ne7 Nxf6#
    5. Left as an exercise for the reader. ;)
  29. Nightrider chess.
  30. Kamikaze chess.
    1. 1.e4 f5 2.Qf3 fxe4 3.Qf7#
    2. 1.e3 d5 2.Ke2 Qd6 3.Kf3 Bg4#
    3. 3... Qd6-b4#
    4. 3... Qd6-f4#
    5. 3... Qf6-d4#
    6. 3... Qd5-e4#
    7. 3... Qd4-e4#
    8. 1.e4 f5 2.Qg4 Kf7 3.Bc4+ Kf6 4.e5#
    9. 4.Bd2-g5#
    10. 4.Qd4-c5#
    11. 1.d3 d5 2.Kd2 Qd7 3.Kc3 d4+ 4.Kb3 Qa4#
    12. 4... Qa3-b4#
    13. 4... Qb5-g5#
    14. 4... Qg6-g5#
    15. 4... Qd5-e5#
    16. 4... Qd5-g5#
    17. 4... Qc3-d4#
    18. 4... Qe7-e4#
    19. 4... Re4-e1#
    20. 1.e3 Nf6 2.Be2 Ne4 3.Bh5 Nxd2 4.Qd5 g5 5.Qxf7#
    21. 1.d4 d6 2.Qd3 Kd7 3.Qa3 Kc6 4.d5+ Kb6 5.Qa5#
  31. Hoppers.
    1. 1.e4 b5 2.Ke2 b4 3.Kf3 b3 4.Ba6 bxa2 5.Bb7 axb1=G 6.Ra6 Gb1-b3 7.Rb6 Gb3xb7+
    2. 1.d4 d6 2.d5 Be6 3.d5xBe6 Nd7 4.e6xNd7#
    3. 1.d4 Nh6 2.Gd5 Nf5 3.Gg5 Rg8 4.GxRg8#
    4. 1.d3 d5 2.Bd2 d4 3.Bc3 dxc3 4.Nd2 cxd2#
    5. 1.Nc3 d5 2.Ne4 dxe4 3.d3 e3 4.Bd2 exd2#
    6. 1.e3 d5 2.Ke2 Bg4+ 3.Kd3 Nd7 4.Nc3 Nc5# or 4... Ne5#
    7. 1.Nh3 Qd8f6 2.Nf4 Qf6f3 3.g3 Qf3h3 4.Ng2 Qh3xh1#
    8. 1.RHa3 a5 2.RHa6 Nf6 3.RHg6 Ng8 4.RHxNg8#
    9. 1.f4 d5 2.Kf2 Qd6 3.Kg3 Qg6+ 4.Kh4 h5#
    10. 1.f4 c6 2.Kf2 Qa5 3.Kg3 Bf8d6+ 4.Kh3 Qh5#
    11. 1.d4 BHe6 2.d5 d6 3.d5xBHe6 Nd7 4.e6xNd7#
    12. 1.Nh3 Qd8f6 2.Nf4 Qf6f3 3.g3 Qf3h3 4.Nd3 Qh3xh1#
    13. 1.Nh3 Qd8f6 2.Nf4 Qf6f3 3.g4 Qf3h5 4.Nd3 Qh5xh1#
  32. .
    2. Left as an exercise for the reader. ;)