, Muskogee, OK

February 21, 2013

Horseshoes and chess: What is black’s best move?

By Eric Morrow
Chess Corner

— World Chess Champion Vishy Anand won the annual chess tournament at Baden-Baden, Germany this February. Amercian-Italian Fabiano Caruana rebounded from his recent slump to place second.

This week’s position is from Anand’s game against Germany’s Arkadij Naiditsch. Naiditsch is white; Anand, black. Anand’s advanced h2 pawn and supporting h1 rook indirectly pin white’s king and rook, or else black’s h2 pawn promotes safely on h1. With this hint in mind what is black’s best move?

Anand bullied white’s king with a check from d3 by advancing his d4 pawn. If the king snatches the poisoned pawn on d3, black’s rook slides over to d1, checking white’s king from a safe square. Irrespective of where the white king moves, black’s h2 pawn next promotes on h1 under the protection of its d1 rook.

Naiditsch therefore retreated his king to d2. From here, white’s position is compromised. On the one hand, white’s rook is well posted at h7, where it is the source of electricity feeding a fence line along the 7th rank that pens in Anand’s king.

On the other hand, the white rook cannot remain on the 7th rank. This is because the white rook must not abandon the “h” file, or the black rook checks white and the h2 pawn promotes. If white’s king first takes the black rook, the h2 pawn promotes with check.

Because of this, Anand subtly forced the white rook to eventually abandon the 7th rank. He moved his king to a8 (Ka8). Now all moves are bad for white. White’s king is paralyzed. All moves lose quickly to a rook check. Advancing the a6 pawn to a7 is wrong, because black patiently moves its d6 pawn to d5 and white is in zugzwang – the German term for when having the move is bad because any move worsens your position. White’s rook must move, and moving off the 7the rank loses the pawn while defending the pawn along the 7th rank loses to a black rook check.

After Anand played Ka8, Naiditsch was thus forced to let the white king out of its cage on the 8th rank, as he moved his rook to h5.

Black’s king soon captured white’s a6 pawn and joined its subjects on the king-side in an overwhelming attack. Naiditsch then surrendered.

This lesson this week is that advancing a pawn to within one square of promotion often creates decisive tactical threats. In this sense, close counts both in horseshoes and chess.