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 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)
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)
