Pin in chess: absolute and relative pins explained
A pin is an attack on a piece that cannot move away without exposing a more valuable piece behind it. Bishops, rooks and queens pin, because they attack along lines.
A pinned piece is half a piece: it cannot run, and often it cannot defend either.
Absolute pin
When the piece behind is the king, the pin is absolute: the pinned piece may not move at all, because the move would put its own king in check.
Relative pin
When the piece behind is not the king, the pin is relative: the pinned piece may move, but its side loses what stands behind it. Here the knight on f6 could move away, but then White would take the queen on d8.
Attack the pinned piece
A pinned piece cannot escape, so attack it again, ideally with a pawn. It will fall.
Exercise: pin the queen
White to move and win the queen.
Make the move on the board: drag a piece, or click it and then a square.
Solved!
Bc4 pins the queen to the king on g8: it cannot leave the diagonal. The best Black can do is Qxc4, and White takes back: the queen is lost for a bishop.
Key points
- A pin attacks a piece that shields a more valuable piece behind it.
- Pinned to the king, a piece cannot move at all; pinned to anything else, it can, but at a cost.
- Attack pinned pieces again, preferably with pawns, and do not leave your own pieces pinned.