Fortress

I was looking through a game played in 1996 and published in Chess Informant 65. Veselin Topalov and Boris Gelfand played an instructive endgame. Gelfand annotated the game for Informant. I studied the game as played, studied Gelfand's annotations, and with the engine running mistakenly thought that Topalov had a decisive advantage. Hence, I overlooked the game result. I tried to repeat Topalov's apparent success against Stockfish 11.

Naturally, I failed. Gelfand anticipated my failure in his annotations, which I should have studied with greater attention.

Black to move

Stockfish 11 64 POPCNT -- Stripes,J
Blitz 15m+10s, 04.06.2020

44...a5

Gelfand gave this move an explanation mark, as it is the only move with winning chances.

45.Kf3 24 a4 46.Kg4

Gelfand played 46.Ke2, and after 46...a3, sacrificed a pawn. 47.b6 cxb6 48.Nc1 Kc5 49.Kd3 Bf4 and the game was drawn ten moves later, but my chess engine says that Black has a decisive advantage. Many years of using chess engines should have taught me however, that -+ with a score in the neighborhood of -2.50 is not yet a won game.

White to move

After 49...Bf4

My play against the engine continued:

46...a3 47.Nc1 Kc5 48.Kf5

Black to move

48...Bb2

Gelfand's annotations offer 48...Kd4 here as unclear, but it is probably a draw.

49.Na2 Kd6 50.Nb4 Kc5 51.Na2 Kxb5 52.e5 Kc5 53.d6

Black to move

53...Kc6

There were a couple of ways to lose here.

a) 53...cxd6 54.e6 Kc6 55.Kg6+-

b) 53...Bxe5 54.d7+-

54.Nb4+ Kd7 55.dxc7 Kxc7 56.Ke4  Bxe5 57.Kxe5 a2 58.Nxa2 ½–½

I tried a second time against Stockfish. This time play began with Gelfand's suggested alternative to Topalov's choice.

Black to move

Stockfish 11 64 POPCNT -- Stripes,J.
Blitz 15m+10s, 04.06.2020

49...b5

Topalov played 49...Bf4, as noted in my note above.

50.Kc2 Kc4 51.d6 Bxd6 52.Nb3 Be5 53.Na5+ Kc5 54.Kb1 Kb6 55.Nb3 b4 56.Ka2

Black to move

White has a fortress very much like the one that Gelfand constructed in the actual game, whci was played at Wijk aan Zee in 1996 and published as Informant 65/588.

56...Kb5 57.Nc1 Kc4 58.Nb3 Bb2 59.Nd2+ Kd3 60.Nb3 Kxe4 61.Na5 Kd4

White to move

62.Kb3 Kc5 63.Kc2 Kb5 64.Nb3 Be5 65.Kb1 Kc4 66.Ka2 Bf4 67.Na5+ Kc3 68.Nb3 Bc7 69.Nc5 Kc2 70.Nb3 Bb6

White to move

I had worked hard to reach the position, and then just before Stockfish moved, I saw why it was not winning.

71.Nd4+!

71...Bxd4 is stalemate.

71...Kc1 72.Nc6 Bc5 73.Na5 Kc2 74.Nb3 Bb6 75.Na1+ Kc3 76.Nb3 Kc2 ½–½