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MatPlus.Net Forum General Fastest stalemate by castling, promotion, and en passant 



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  (1) Posted by Rewan Demontay (Real Name: James Malcom) [Saturday, May 23, 2020 04:08]; edited by Rewan Demontay (Real Name: James Malcom) [200523]  Fastest stalemate by castling, promotion, and en passant I had some ideas for shortest stalemate games: stalemate via castling, promotion, and en passant. Of course stalemate by en passant is arbitrary, but it is a bit of a challenge since the captured pawn has to stay still. Each respective move must be the only way to give a stalemate.
Here are my tries. Who can improve or prove optimal?
Castling31 Ply
I'm almost sure that this might be optimal.
(= 13+2 )
1. f4 e5 2. fxe5 d6 3. exd6 Qg5 dxc7 Qxg2 5. cxb8=Q Qxh2 Qxa7 Qxg1 7. Qxa8 Qg2 8. Bxg2 g5 9. Qxb7 g4 10. Qxc8+ Ke7 11. Qxf8+ Ke6 12. Qxf7+ Ke5 13. Qxg8 Kf4 14. Qxh8 h5 15. Qxh5 Kg3 16. OO
En Passant29 Ply
(= 16+3 )
1. e4 h5 2. Qxh5 d5 3. Qxd5 g5 4. h4 b6 5. Qxa8 Ba6 6. Qxa7 e5 7. Qxb8 Bb5 8. Bxb5+ Ke7 9. Qxc7+ Ke6 10. Qxd8 Be7 11. hxg5 Bf6 12. Qxg8 Be7 13. Qxh8 Bf8 14. Qxf8 f5 15. gxf6
Queen Promotion27 ply
(= 15+4 )
1. e4 d5 2. exd5 e6 3. dxe6 h5 4. Qxh5 Na6 5. Bxa6 bxa6 6. Qxh8 c6 7. e7 Kd7 8. Qxg8 Kc7 9. Qxf8 Kb8 10. Qxg7 f6 11. Qxf6 Bd7 12. Qxc6 Be6 13. Qxa6 Bc8 14. exd8=Q
Rook Promotion33 Ply
(= 16+3 )
1. e4 h5 2. Qxh5 a5 3. Qxa5 g5 4. h4 Bh6 5. hxg5 Nf6 6. gxh6 OO 7. h7+ Kg7 8.
Qxa8 d6 9. Qxb7 Bf5 10. exf5 Ng8 11. Qxb8 f6 12. Qxd8 Nh6 13. Qxc7 Rd8 14. Qxd8
Kf7 15. Qxd6 Kg7 16. Qxe7+ Nf7 17. h8=R
Bishop Promotion29 Ply
(= 15+3 )
1. e4 d5 2. exd5 e6 3. dxe6 h5 4. Qxh5 Na6 5. Bxa6 bxa6 6. Qxh8 c6 7. e7 Kd7 8.
Qxg8 Kc7 9. Qxf8 Kb8 10. Qxg7 f6 11. Qxf6 Bd7 12. Qxc6 Be6 13. Qxe6 Kc7 14. Qxa6
Kb8 15. exd8=B
Knight Promotion27 Ply
(= 15+3 )
1. e4 h5 2. Qxh5 Na6 3. Bxa6 bxa6 4. Qxh8 d6 5. Qxg8 Bf5 6. exf5 g6 7. fxg6 Kd7
8. Qxf8 Kc8 9. Qxe7 c6 10. Qxd6 Kb7 11. Qxc6+ Kb8 12. Qxa6 Qd7 13. gxf7 Qe8+ 14.
fxe8=N   (2) Posted by François Labelle [Sunday, May 24, 2020 21:08]  Here are some improvements. Same final positions, just a faster way to reach them.
En Passant28 Ply
(Black starts. Flip the board to start with White.)
1...b6 2.e4 h5 3.Qxh5 d5 4.Qxd5 e5 5.Qxa8 g5 6.Qxb8 Kd7 7.Qxa7 Ke6 8.Qxc7 Ne7 9.Qxd8 Nf5 10.Qxf8 Ng3 11.hxg3 Rh4 12.gxh4 Ba6 13.hxg5 Bb5 14.Bxb5 f5 15.gxf6 e.p.
Queen Promotion25 Ply
1.e3 b5 2.Bxb5 c6 3.Bxc6 h5 4.Bxd7+ Kxd7 5.Qxh5 f5 6.Qxh8 f4 7.exf4 g5 8.fxg5 Bh6 9.Qxh6 Na6 10.Qxa6 Nf6 11.gxf6 Kc7 12.fxe7 Kb8 13.exd8=Q
Rook Promotion31 Ply
1.e4 h5 2.Qxh5 d5 3.Qxd5 f6 4.Qxb7 Bf5 5.exf5 Qd6 6.Qxa8 Qg3 7.hxg3 Rh4 8.gxh4 Nh6 9.Qxa7 Nf7 10.Qxc7 g5 11.hxg5 Bh6 12.gxh6 Na6 13.h7 Nc5 14.Qxc5 Kf8 15.Qxe7+ Kg7 16.h8=R
Bishop Promotion27 Ply
1.e3 b5 2.Bxb5 c6 3.Bxc6 h5 4.Qxh5 e6 5.Qxh8 Nxc6 6.Qxg7 Nd4 7.exd4 Bc5 8.dxc5 d6 9.cxd6 Kd7 10.Qxf7+ Ne7 11.dxe7 Kc7 12.Qxe6 Ba6 13.Qxa6 Kb8 14.exd8=B
All the solutions were found with Jacobi, but maybe other programs work too. The Rook Promotion solution was found using "PG demolition mode". The position cannot be reached in 29 plies but I'm not sure about 30 plies yet.   (3) Posted by Rewan Demontay (Real Name: James Malcom) [Monday, May 25, 2020 02:46]  Nice job and many thanks Francios! I knew for sure that the rook could be improved, and the time save for all of the pawn marches with welltimed captures is very neat to see.
The en passant flip isn’t too much of a surprise for either of us, I think. Here is the flipped notation for myself and others: 1. b3 e5 2. h4 Qxh4 3. d4 Qxd4 4. e4 Qxa1 5. g4 Qxb1 6. Kd2 Qxa2 7. Ke3 Qxc2 8. Ne2 Qxd1 9. Nf4 Qxf1 10. Ng6 hxg6 11. Rh5 gxh5 12. Ba3 hxg4 13. Bb4 Bxb4 14. f4 gxf3
Do you think that the castling and knight promotion are optimal?   (4) Posted by Andrew Buchanan [Monday, May 25, 2020 04:42]; edited by Andrew Buchanan [200525]  I would be tempted to start with a matrix like https://pdb.dieschwalbe.de/P0002321 and see if it might be possible to adapt it so that castling is the only move.   (5) Posted by Rewan Demontay (Real Name: James Malcom) [Monday, May 25, 2020 04:47]; edited by Rewan Demontay (Real Name: James Malcom) [200525]  Perhaps, but I'm not too sure. Then again, I am heavily biased here. :)   No more posts 
MatPlus.Net Forum General Fastest stalemate by castling, promotion, and en passant 


