The theme for this problem set is pins: situations in which a piece cannot move, because it screens a player’s king from check. (Under the rules of chess, you’re never allowed to make a move that puts your own king in check.)
In this simplified position, for example, Black’s rook, bishop, and pawn are all pinned:
So White can play either
- rook takes bishop, checkmate!
- queen takes bishop, checkmate! or, most dramatically,
- queen takes pawn, checkmate!
In each case, Black can’t recapture, because the pieces needed to do the job are pinned. So near, and yet so far! (Do you see why, after White plays queen takes pawn, neither Black’s rook nor bishop can capture the queen?)
Now, on to the real problems. Each is a “forced mate in two”: White moves, then Black moves, then White checkmates no matter what Black tries to do: