It’s Your Move: daily chess puzzle # 205

Black to play: in the game, a draw was agreed here. Was it correct?

Tigran Petrosian v Lothar Schmid, Bamberg 1968

Solution

The answer, as always with puzzles, is no! 1…b5! and Black wins by zugzwang, 2 Kc3 bc 3 Kc4 a6 and White must retreat his Nd5, losing his f4 pawn.

Looking at the game, it was virtually dead level throughout, and so maybe the players, even of their class, were playing the draw out. White should a move or two before have captured on f4 with his Nd5, then both g pawns get exchanged, result equality.