Bishop (chess)
From Tardis Wiki, the free Doctor Who reference
The Bishop was a chess piece used when playing games of chess. Both players could use two of them, either black or white.
The Fourth Doctor captured one of K-9's bishop when they played a game of chess. However, K9 noted the Doctor's move had enabled him to set him up for Checkmate in six moves. (TV: The Sun Makers)
Gantok, when facing the Eleventh Doctor in a game of live chess, needed to move his queen piece to bishop four to stay in the game but was unable to as four million volts were running through it. (TV: The Wedding of River Song)
Mr Clever noted how the Eleventh Doctor would have to use his queen piece to take his attacking bishop to stand a chance of defeating him in their game of chess. (TV: Nightmare in Silver)
