Gary Gifford wrote on Fri, Jul 18, 2008 07:49 AM UTC:
If your King is in check you must do one of the following: (a) move your king out of check, (b) block the check (interpose), or (c) capture the checking piece or pawn. b and c do not work in cases of double-check and b will not work against knight checks.
You could not checkmate your opponent while leaving your own king in check.
You could not checkmate your opponent while leaving your own king in check.