2 The pin
Three pieces are involved in a pin; they are all on the same file, rank or diagonal.
- A long-ange piece 1, i.e. a bishop, rook or queen moving along that file, rank or diagonal.
- An opposing piece 2 which is being attacked by the first piece. This is the pinned piece.
- An opposing piece 3 which is hidden behind piece 2 and which if piece 2 (the pinned piece) was moved could be taken by piece 1.
A pin allows long-range pieces such as the bishop or rook to win high value material. Take care in the opening if you queen is on an open file in front of your king.