Absolute Pin

An absolute pin is a tactic where a piece cannot legally move because doing so would expose its king to check.

Example 1:

1.Nxd4! White captures a pawn, luring blacks rook to capture, or else black will need fight in a bad endgame as the two pieces are better than the rook.

1...Rxd4 2.Bc3!

White's bishop pins the black rook to the king, winning the rook in the process.

Example 2:

1.Rxe5! Rxe5 - Black's king can't let go of the rook, White uses this: 2.g3!

Since 2...g4 doesn't help Black as White will just move his king and Black is in Zugzwang, he decides to play 2...f4 White responds with 3.g4!

3...f3 4.Kg1 +- Black is now in Zugzwang!