Learn How to Pin: Mate in 3
This middlegame puzzle shows how a pin can become the start of a forced mating net. White’s active bishop and queen coordinate against a vulnerable king, while Black’s pieces are overloaded and the back rank is loose. The key idea is to use a forcing check that restricts the defender’s choices and drags a piece into a passive square. Once the king is boxed in, the remaining moves are all about maintaining the pin and converting it into checkmate.