Captured pieces switch sides and join your army.
How to play
Captured pieces switch sides! When you capture, the captured piece changes to your colour and reappears on the square your capturing piece just left (a pawn landing on its promotion rank becomes a queen). Check rules apply: you may not leave your king in check (counting the piece that just switched sides) or castle out of or through check. Checkmate wins; stalemate is a draw. You play White.