Engine says, "Mistake," I say, "Great." Here's why:

[echo girder]

The move is 36. c5?

I have the black pieces and am down material. We have just our rooks, pawns, and kings, and I'm scrambling for a way to find a draw. In this position, c5 is a mistake, according to the engine, because b5 would create a threat to win a pawn, where c5 allows my opponent to activate their king off the back rank.

HOWEVER

I'm playing a human, and I was confident that my opponent, after c5, would play the perfectly natural-looking d5 in response. In this position, d5 looks great because it creates a passed pawn AND checks the king simultaneously. Who wouldn't do that? My opponent plays d5.

Problem is, d5 is a blunder because after Kd6, white's winning chances are eliminated, and, with accurate play, I was able to force a draw by insufficient material.

https://www.chess.com/analysis/game/daily/458589561?tab=review

[terse copper]

Calybaby (1223) vs. jasondolley (1564)

Move List

1. e4 e6 2. Bc4 [d5] 3. exd5 exd5 4. Bb3 g6 5. d4 Bg7 6. Nf3 Nf6 7. O-O O-O 8. c4 Nc6 9. Nc3 Be6 10. Ng5 Ne7 11. Nxe6 fxe6 12. Re1 Qd7 13. Bf4 dxc4 14. Bxc4 Nfd5 15. Be5 Bxe5 16. Rxe5 Rae8 17. Qb3 c6 18. Rae1 Nf5 19. Qd1 Nxc3 20. bxc3 Ng7 21. Qg4 Qf7 22. R1e2 h5 23. Qg5 Kh7 24. Bd3 Qf6 25. g4 Qxg5 26. Rxg5 Rf6 27. gxh5 Nxh5 28. Rxh5+ Kg7 29. Rg5 Rh8 30. c4 Rh3 31. Bxg6 Rxg6 32. Rxg6+ Kxg6 33. Rxe6+ Kf7 34. Re3 Rh4 35. Rd3 Ke6 36. f3 c5 37. d5+ Kd6 38. Rc3 a6 39. a4 b5 40. axb5 axb5 41. cxb5 Kxd5 42. Rd3+ Kc4 43. Rd8 Kxb5 44. Kg2 c4 45. Kg3 Rh5 46. h4 c3 47. Rd1 Kb4 48. Kg4 c2 49. Rc1 Rc5 50. h5 Kb3 51. h6 Kb2 52. h7 Rc8 53. Rxc2+ Kxc2 54. Kg5 Rc5+ 55. Kg6 Rc6+ 56. Kg7 Rc7+ 57. Kg6 Rc6+ 58. Kg5 Rc5+ 59. Kg4 Rc4+ 60. f4 Rc8 61. Kg5 Rh8 62. Kg6 Kd3 63. f5 Ke4 64. f6 Ke5 65. Kg7 Rxh7+ 66. Kxh7 Kxf6