King cannot take queen because then he is in check by bishop.
A rule in chess I'm unsure about. Can anybody help me?
No. You cannot put yourself in check (Even if you are already in check)
Think of it this way: Black will take your king before you take his.
Think coffeehouse chess rules: once someone lets his king get captured, the game is over!
In other words, any move that lets the king be captured next move is illegal. If no legal move is available then it is either checkmate or stalemate, depending on whether the king is in check.
The King taking the Queen would be moving into check, which is illegal. The "pinning" of the bishop is irrelevant.
Let's play the 'how many people can answer the same question?' game.
I'll continue: No, because you can't move into check, even if the piece is pinned.
Why do so many people ask this question? If you are confused about a rule, Google the rules of chess. By simply having a basic knowledge of the rules of the game you are playing, you won't have to ask questions that would be answered if you knew how to play the game. Sorry if that sounded harsh, but if you are going to play a game, LEARN THE RULES! :P
White to play
Thanks