Pin the Knights
Pinning knights with Bishops is probably the most common chess tactic. It occurs very early in many games, in the openings. If your Knight is out on the Kingside or Queenside, one of the enemy Bishops can pin it to your Queen or King. And if you see your enemy has a Knight out, consider using a Bishop to pin it.
Diagram: Pin the Knight with Bishop
Double Up on a Pin
Sometimes you can “double up” on a pinned Knight, and win it (or win at least a pawn). So pinning is desirable for you, and should be carefully looked at if your opponent has done it. The threat is not so much an exchange of Bishop-takes-Knight, which is actually often a bad move because Bishops are worth a bit more than 3 pawns, whereas Knights are worth 3 pawns. In beginner chess, swaps of Bishops for Knights don’t really make much difference. But the greater risk of a pinned knight is the idea of doubling up on the pinned knight.
Biff the Pinning Bishop
A good response is often to “biff the bishop” with a pawn. Biffing means moving a rook pawn upwards one square to attack the Bishop. The Bishop can then swap itself for the Knight, or can retreat backwards.
Diagram: Biff the Pinning Bishop
Protect the Pinned Knight
Diagram: Protect the Pinned Knight with Another Knight
Unpin the Knight
Diagram: Unpin the Knight with Bishop
Unpinning the Knight can also mean castling, to get the King away so that the Knight is not pinned to the King. Unpinning a Knight that is pinned to the Queen may involve moving the Queen away, ideally with a Queen check (not always possible).
Related Chess Tactics
Read more about these related chess strategies: