Purge Chess invented by Andy Lewicki is a solitaire puzzle game played on a 4x4 or 6x6 board with 2 types of chess pieces (Bishops and Knights; 8 pieces each for 4x4, 18 pieces each for 6x6 board). All pieces are randomly placed on the board. Each move must be a killing move.
The aim is to clear the board with only one piece surviving at the end of the game (either a Bishop or, a Knight).
The puzzle ends when no killing move can be made.