22 upvotes, 1 direct replies (showing 1)
View submission: xkcd 3045: AlphaMove
Just ran through a game where both sides used this algorithm. If I didn't make a mistake (big if), the game ends on move 17 in a draw due to repetition. The game features underpromotion, en passant, and not a single check.
PGN: 1. e4 e6 2. f3 f5 3. e5 g5 4. d4 c6 5. d5 exd5 6. f4 g4 7. h4 gxh3 8. Kd2 h5 9. Kc3 h4 10. Kd2 hxg2 11. Ke1 gxh1=B 12. Kd2 d6 13. exd6 Kd7 14. Kc3 Ke8 15. Kd2 Kd7 16. Kc3 Ke8 17. Kd2 Kd7
Comment by MegaIng at 03/02/2025 at 18:26 UTC
2 upvotes, 1 direct replies
Pretty sure your code has a bug, mine starts diverging at move 4. I suspect mine matches what was intented since it does get 6 Knights on the board, which you version doesn't.
This is what I got for the PNG: 1. e4 e6 2. f3 f5 3. e5 g5 4. d4 d5 5. exd6 g4 6. d7+ Kf7 7. dxc8=N Ke8 8. fxg4 h6 9. gxf5 Kd7 10. g4 h5 11. fxe6+ Ke8 12. g5 Na6 13. h3 Nc5 14. h4 Ne7 15. Kd2 Ne4+ 16. Ke1 Nf5 17. g6 Nf6 18. g7 Ng3 19. gxf8=N Nge4 20. Ke2 Ng4 21. Kf3 Ngf2 22. Ke2 Nh3 23. Ke3 Nhf2 24. Nb6 Nh3 25. Na4 Nhf2 26. Nac3 Nxc3 27. Kxf2 Nxd1+ 28. Kf3 Qc8 29. c4 Ne3 30. Ke4 Nf5 31. Kd3 Ng3 32. e7 Nxh1 33. Kc2 Qb8 34. d5 Kxe7 35. d6+ Kf6 36. dxc7 Nf2 37. c8=R Ng4 38. Kd2 Nh2 39. Ke3 Ng4+ 40. Kd4 Nh2 41. Kd5 Nxf1 42. Nc3 Nh2 43. Nce2 Ng4 44. Nd4 Nh6 45. Nd7+ Kf7 46. Ndf3 Qd6+ 47. Ke4 Qd2 48. Nf8 Qd5+ 49. Ke3 Qd2+ 50. Ke4 Qd5+ 51. Ke3 Qd2+ *