India, Nov. 18 -- Arjun Erigaisi's gaze shifted from the chess board to the ceiling. His glance moved across the grand hall of a posh Goan hotel, as he sat, calculating the next few possible moves, predicting his opponent's reaction, and the probability of a favourable outcome with a singular shift of a chess piece.

On the board in front of him, he had a few options. Among those was his innocuously placed white bishop that could change the course of the game. Computer engines suggested that on the 24th move the bishop be moved from g2 to d5.

The bishop would then - in all likelihood - be taken by the black queen immediately, but it would set Erigaisi on the path to a famous win in the quarter-final of the Chess World Cup, over Chinese G...