For once, chess-blindness struck the other guy!

Yesterday my opponent playing White in this Correspondence Chess game resigned after losing his Knight to my pawn at 49…axb3, giving me the win by default.
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White was right to surrender at this point, there was no way he could prevent the promotion of my pawn to another Queen, giving my Black army an awesome advantage, without losing his Rook in the process. Either way, my material advantage would be enough to guarantee my checkmating his King eventually.

Our play in this game had been pretty evenly matched until White, struck by chess-blindness in the last few moves, apparently forgot about the offensive power of that humble pawn my Rook had been defending for so very long.

The full move record of this game, with illustration and annotation for the final few moves.

1. e4 e5 2. Nf3 Nc6 3. Bc4 h6 4. c3 Nf6 5. d4 d6 6. Be3 d5 7. exd5 Na5 8. Bb5+ Bd7 9. Ba4 Nxd5 10. Bd2 exd4 11. Qe2+ Be7 12. Na3 Bxa4 13. Nxd4 O-O 14. O-O c5 15. Nf3 a6 16. Ne5 Bf6 17. Rfe1 Re8 18. f4 Nc6 19. Qf2 Nxe5 20. fxe5 Bxe5 21. Qxc5 b6 22. Qc4 Qd7 23. Qh4 Bf6 24. Qg3 Rxe1+ 25. Rxe1 Re8 26. Rf1 Be5 27. Qd3 Nc7 28. Qxd7 Bxd7 29. Nc4 Bb5 30. b3 Re6 31. Re1 f6 32. Nxe5 Rd6 33. c4 Rxd2 34. Nf3 Rxa2 35. cxb5 Nxb5 36. Rc1 Kh7 37. h3 Rb2 38. Rc6 Rb1+ 39. Kh2 Rxb3 40. Rxb6 Ra3 41. Nd2 Nd4 42. Rd6 Ra4 43. Rd7 Ne2 44. Rd5 Nf4 45. Rd6 Ra2 46. Rd4 Ne2 47. Rd6 a5 48. Nb3
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At this point I thought his Knight move to b3 was intended to defend the d2 square, from where his Rook could fork-attack my Rook and Knight. So advancing my a-pawn seemed the only sensible thing to do.
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48…a4
When White moved his Rook to the a file, ..
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49. Ra6
… my pawn captured his Knight 49… axb3, see the board diagram at the top of this post, and defending my Black Rook. White then decided to resign the game, giving me the win.
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Chess-blindness is such a cruel, cruel thing.