Curious Matt legally created, just discovered

[chessica]

[d]8/8/8/8/8/8/2k5/RNBQKBNR b - - 60 151

[Jouni]

Game here:
[pgn]
1. d4 d6 2. Bf4 Nf6 3. e3 Nbd7 4. h3 e5 5. Bh2 ed4 6. ed4 g6 7. Nf3 Bg7 8. Bd3 O-O 9. O-O Re8 10. c3 Nf8 11. Nbd2 Bd7 12. a4 a5 13. Qb3 b6 14. Bb5 Bb5 15. Qb5 Qd7 16. Qd7 N6d7 17. Rfe1 f5 18. Nc4 h6 19. Kf1 Kf7 20. Na3 Re1 21. Ne1 Ne6 22. Nb5 Rc8 23. Bd6 c6 24. Na7 Re8 25. Nc6 Ng5 26. f3 Bf6 27. Nd3 Re6 28. Nce5 Kg7 29. Nd7 Rd6 30. Nf6 Kf6 31. Re1 Ne6 32. Ke2 h5 33. h4 Rd5 34. Kd2 Rd6 35. g3 Nc7 36. Re5 Ne6 37. Ke3 Kf7 38. Nf4 Nc7 39. c4 Rc6 40. b3 Rd6 41. d5 Na6 42. Nd3 Nc7 43. Kd4 Ne6 44. Re6 Re6 45. de6 Ke6 46. Nf4 Kf6 47. Nh3 Ke6 48. f4 Kd6 49. Ng5 Kc6 50. Nf3 Kd6 51. Ne5 g5 52. fg5 Ke6 53. Nd3 f4 54. Nf4 Kf5 55. Ke3 b5 56. ab5 a4 57. ba4 Ke5 58. Nd3 Kf5 59. Kf3 Kg6 60. Ke4 Kg7 61. c5 Kf7 62. a5 Kg7 63. Ke5 Kg6 64. Ke6 Kg7 65. Kf5 Kf7 66. Nf4 Kg7 67. Ne2 Kh7 68. Nd4 Kg7 69. Nf3 Kf7 70. g6 Kg7 71. Kg5 Kg8 72. Kh5 Kg7 73. Kg5 Kg8 74. h5 Kh8 75. h6 Kg8 76. Kf6 Kf8 77. Ke6 Ke8 78. g4 Kd8 79. g5 Kc7 80. h7 Kb7 81. h8B Kc7 82. g7 Kb7 83. g8B Kc7 84. Bh7 Kb7 85. Bc2 Ka7 86. Bd3 Kb8 87. Bf1 Ka8 88. Bc3 Kb7 89. Bd2 Ka7 90. Bc1 Ka8 91. g6 Kb8 92. g7 Kc8 93. g8Q Kb7 94. Qg2 Ka7 95. Qe2 Kb8 96. Qd1 Ka7 97. Kd5 Kb8 98. Nd4 Kc7 99. Ne2 Kd7 100. Ng1 Ke7 101. Kc4 Kf6 102. c6 Ke7 103. b6 Ke6 104. a6 Ke5 105. a7 Ke4 106. b7 Kf5 107. Kb5 Kf6 108. Kb6 Ke6 109. Kc7 Kf7 110. Kb8 Kg7 111. a8R Kg6 112. Ra1 Kf6 113. Kc7 Kf7 114. b8R Kg7 115. Rb2 Kf6 116. Rh2 Ke6 117. Rh1 Kf7 118. Kb6 Kf6 119. Kb7 Ke5 120. c7 Ke6 121. c8N Kf7 122. Nb6 Kg6 123. Na4 Kf6 124. Nc3 Kf5 125. Nb1 Kg6 126. Kb6 Kf5 127. Kb5 Kf6 128. Kb4 Ke5 129. Kc3 Ke6 130. Kd2 Kd6 131. Ke1 Kc7 132. Qe2 Kc6 133. Qg2 Kb6 134. Rh3 Kc7 135. Rf3 Kb6 136. Qg4 Kc7 137. Rf5 Kd8 138. Qg6 Ke7 139. Rf6 Kd8 140. Qg7 Ke8 141. Qf8 Kd7 142. Rd6 Kc7 143. Rd8 Kb6 144. Qe7 Kc6 145. Rd6 Kc5 146. Qc7 Kb4 147. Rd2 Kb3 148. Rh2 Kb4 149. Rh1 Kb3 150. Qd6 Kc2 151. Qd1#[/pgn]

[Brunetti]

Game here:

151 moves! Here's something a little shorter (and I think it's easily improvable):

[pgn]
[White "Alex"]
[Black "Black"]
[Result "1-0"]

1. e4 d5 2. Qh5 dxe4 3. Qxh7 b5 4. Qxh8 b4 5. Qxg8 b3 6. Qxg7 bxa2 7. Qxf8+ Kd7
8. Qxf7 Kc6 9. Qxe7 Na6 10. Qxd8 Nb4 11. Qxc8 Nxc2+ 12. Ke2 Ne3 13. Qxc7+ Kb5
14. Qxa7 Kb4 15. Qxa8 Nxg2 16. Qxa2 Ne3 17. Qe6 Ng4 18. Qxe4+ Kb3 19. h3 Nxf2
20. Ke1 Nxh3 21. d3 Nf2 22. Bf4 Kxb2 23. Bc1+ Kb3 24. Qf5 Nxd3+ 25. Kd2 Nf2 26.
Qg4 Nd1 27. Ke1 Kc2 28. Qxd1#
[/pgn]
Alex

[Jouni]

Thanks! The original youtube mate was clearly unnecessary long.

[petero2]

[pgn]
[Event "?"]
[Site "?"]
[Date "2024.10.07"]
[Round "-"]
[White "?"]
[Black "?"]
[Result "1-0"]

1. b4 c5 2. bxc5 b5 3. cxb6 d5 4. bxa7 Kd7 5. axb8=Q Rxa2 6. Qxc8+ Qxc8 7.
Rxa2 Qxc2 8. Qxc2 Kd6 9. Qxh7 Kc5 10. Qxg7 Rxh2 11. Qxf7 Rxg2 12. Qxe7+ Kc4
13. Qxf8 Rxf2 14. Qxg8 Kb3 15. Ra1 Rxe2+ 16. Kd1 Rxd2+ 17. Ke1 Kc2 18. Qxd5
Rd1+ 19. Qxd1#
{White mates} 1-0
[/pgn]

[Ajedrecista]

Hello:

Thanks! The original youtube mate was clearly unnecessary long.

To put it in context, here is the video on YouTube:

The Greatest Checkmate Ever Given!

It looks like with RNBQKBNR in the first rank, only the black king on c2 allows such a checkmate, given that the rest of black pieces can not capture the white queen.

------------

[pgn]
[Event "?"]
[Site "?"]
[Date "2024.10.07"]
[Round "-"]
[White "?"]
[Black "?"]
[Result "1-0"]

1. b4 c5 2. bxc5 b5 3. cxb6 d5 4. bxa7 Kd7 5. axb8=Q Rxa2 6. Qxc8+ Qxc8 7.
Rxa2 Qxc2 8. Qxc2 Kd6 9. Qxh7 Kc5 10. Qxg7 Rxh2 11. Qxf7 Rxg2 12. Qxe7+ Kc4
13. Qxf8 Rxf2 14. Qxg8 Kb3 15. Ra1 Rxe2+ 16. Kd1 Rxd2+ 17. Ke1 Kc2 18. Qxd5
Rd1+ 19. Qxd1#
{White mates} 1-0
[/pgn]

Your 37-ply proof game is a true gem! Congratulations, Peter. I have some questions:

- How did you get that short proof game, manually or with the help of a computer? I tried Natch 3.3 unsuccessfully: while it saw no solutions for 11 plies in virtually no time and also no solutions for 13 plies in 0.57 seconds, I had to interrumpt the computation for 15 plies after some minutes, so it is clearly unfeasible to compute 37 plies of your proof game, or even 35 or 33...

- Do you know if 37 plies is the shortest proof game for this position (i.e. a proof via software) or could be further shortened? Thank you in advance.

Regards from Spain.

Ajedrecista.

[Brunetti]

{White mates} 1-0

After some trial and error, I was able to do it in half a move less; I mean, I saved one White move (see move 18):
[pgn]
[White "Alex"]
[Black "Alex"]
[Result "1-0"]

1. g4 h5 2. gxh5 Rxh5 3. e4 Rxh2 4. Qg4 Rxf2 5. Qxg7 Rxd2 6. Qxg8 d5 7. exd5
Qxd5 8. Qxf8+ Kd7 9. Qxc8+ Kc6 10. Qxb8 Rxc2 11. Qxa8 Rxb2 12. Qxa7 Rxa2 13.
Qxb7+ Kc5 14. Qxc7+ Kb4 15. Qxe7+ Kb3 16. Qxf7 Rd2 17. Qxd5+ Kc2 18. Qd8 Rd1+
19. Qxd1#
[/pgn]
That's where I got the idea: with Black, it can be done in 18 moves
[pgn]
[White "Alex"]
[Black "Alex"]
[Result "0-1"]

1. h4 g5 2. d4 gxh4 3. Rxh4 e5 4. Rxh7 Qg5 5. Rxf7 Qxg2 6. Rxd7 exd4 7. Qxd4
Qxg1 8. Rxc7 Qxf1+ 9. Kd2 Qxc1+ 10. Kc3 Qxb1 11. Rxb7 Qxa1 12. Rxa7 Qxa2 13.
Rd7 Qxb2+ 14. Kc4 Qxc2+ 15. Kb5 Qxe2+ 16. Kb6 Qxf2 17. Kc7 Qxd4 18. Rd8+ Qxd8#
[/pgn]
Alex

[petero2]

Your 37-ply proof game is a true gem! Congratulations, Peter. I have some questions:

- How did you get that short proof game, manually or with the help of a computer? I tried Natch 3.3 unsuccessfully: while it saw no solutions for 11 plies in virtually no time and also no solutions for 13 plies in 0.57 seconds, I had to interrumpt the computation for 15 plies after some minutes, so it is clearly unfeasible to compute 37 plies of your proof game, or even 35 or 33...

- Do you know if 37 plies is the shortest proof game for this position (i.e. a proof via software) or could be further shortened? Thank you in advance.

Hi,

I used my own proof game finder, "texelutil proofgame". It is described here

https://github.com/peterosterlund2/texe ... oofgame.md

but the focus in that document is not on finding the shortest possible proof games.

I don't know if 37 plies is the shortest proof game for this position. The program reports that at least 31 plies are needed, but that can easily be proven without computer help. 15 black pieces need to be captured, which requires at least 29 plies, but the first white move cannot be a capture, so at least 31 plies are needed.