Now, the winning move in our second diagram is far from obvious, but the fact that White’s king is on the edge of the board (where mates usually occur!) should set off some sort of mental alarm. I imagine Browne saw that 39…Kd5 turns the game into a pawn race, but his calculation must have been a bit off that day. His analysis probably went like this:

39...Kd5 40.b4 f5 41.b5 f4 42.b6

42...f3 43.b7 f2 44.b8Q f1Q 45.Qb5+ Qxb5+ 46.Kxb5 draw.

The move he must have missed, was...