Kramnik v. Anand

The first of two world chess championship semi-finals matches began last week in Bonn, Germany. Reigning world chess champion Vishy Anand of India is competing against Vladimir Kramnik of Russia. The winner plays the winner of the Gata Kamsky (American)-Veselin Topalov (Bulgaria) match, which begins next month.

As of Sunday, Anand and Kramnik played their fourth game out of a scheduled twelve games. It was a draw, like two of their previous games. However, Anand drew first blood on Friday, as Anand defeated Kramnik with the black pieces.

The critical move in the third game occurred on move 22 in this week's position. Kramnik has sacrificed a piece for a vicious attack. Anand responds by giving back the sacrifice and accepting a two- pawn deficit in order to distill Kramnik’s attack and to initiate an attack of his own. With this hint in mind please try to find black’s best move, as played by Anand.

The position is complicated. Black’s rook at g4 pins white’s g3 pawn and prevents it from taking black's bishop at f4. Meanwhile, white’s rook at d7 dominates the 7th rank and is poised to coordinate with its other pieces for an assault. The quiet pieces amidst these complications is black’s b7 bishop, which patiently controls the a8-h1 diagonal.

Black trades rooks and slides its b7 bishop to f3, attacking whites’ rook at d1. Black’s bishops then continue to harass the rook.

The result of this exchange is that white's attack is weakened, white is up two pawns, and black now has an open “g” file. Anand went on to use this open file to coordinate his rook, bishop and queen in a winning attack.