Fischer's Continuation

In yesterday's "Knight over Bishop," I presented an endgame played by Bobby Fischer. In the comments section, chesstiger offers the analysis: "40. Kf2 is a mistake ... after 40. Kf2 Bc6 41. Nh5+ Kf7," he states "white's advantage is crumbling." Chesstiger's analysis gives us this position with White to move.



The move 40...Bc6 suggested by chesstiger deviates from Wolfgang Unzicker's play in the game. Unzicker played 40...Bd1, and the game ended after 41.Nd7 c4 42.Kg3. From the diagram position, 42.Ke3 looks to be White's best try. I gave it a shot against Hiarcs 12 and was able to win the game.

42...b6 43. Ng3 Kg7 44. Ne4 Kh6 [44...Bd5 complicates matters] 45. Nd6 Kg7



I played 46. c4, which the "explain all moves" feature of Hiarcs calls suboptimal. Better is 46.b3. I was proceeding with a plan to exchange one set of pawns on the queenside with hopes of creating weaknesses my knight could exploit.

46...Bg2 47. Nc8 [the idea behind move 46] 47...b5 48. cxb5 axb5



49. Nd6 Bd5
[If Black tries 49...b4, then 50. a4 creates a passed pawn that will keep the bishop tied down.]

50. a3 [another suboptimal move according to the engine, which prefers 50. b3] 50...Bb3 51. Ne4! [51.Nxb5 is probably okay.]



51... Kh6 [Black chooses which pawn will fall] 52. Nxc5 Bd1 [Black also get to take a pawn] 53. Ke4 Bxg4 54. Ke5

Black to move


Black now has a passed pawn, and might try to get counterplay with 54...Bh3 or 54...Bh5.

Nevertheless Hiarcs played 54...Kg7, which the engine prefers at a search depth of 22 plies. At 16 plies, it calls this move "tactically incorrect."

The game concluded
55. Ne6+ Kf7 56. Nxg5+ Ke7 57. Ne4 Be2 58. Nd6 Kf8
[58...Kd7 is met by 59.f6]
59. Kd5 Ke7 60. Kc5 Bg4 61. Nxb5 Bd1
[61...Bxf5 62. a4 Be4 63. a5 Kd7 64. a6 Bf3 65. Nd6+-]
62. b4 Bh5 63. a4 Bd1 64. a5 1-0

Fischer might have played the immediate 40. Nd7 with several fork threats after 40...Bxg4, as suggested by chesstiger. But, Black can play 40...Kh5, and White still has a lot of work. Fischer's 40.Kf2 threatens the bishop at a moment when Black cannot afford to trade minor pieces.

While I was playing through Fischer's game, I kept thinking the king must become active. Fischer chose the moment to activate his king when it could also make a direct threat--a double attack.