Figure[White to move]

Ganging Up on the Relatively Pinned Piece.

Once you have found or created a relative pin, the process of exploiting it usually resembles the process of exploiting a piece pinned to its king. The visual appearance is a little different, however, and in any event a few positions to reinforce the basic ideas can’t hurt.

In the example to the left, White is thinking about using his bishop to inflict a common pin on Black’s knight with Bg5. Is it worth the bother? Ask what attacking and defending forces each side would be able to summon to the knight’s position. Black could try Kg7, defending the knight; White then has with Qh4, adding a second attacker (or Qc3, making the pin absolute). Now Black is out of resources; he has nothing else he can use to defend the knight, whereas White’s movement of his queen has cleared the way for another attacker: Rf1. White can aim more pieces at the pinned target than Black can rally in reply, so eventually the Black knight will be lost. The pin is well worth playing for White.

As with most of these positions, of course, you should not imagine that all these moves actually would get played. Assuming he anticipates where this sequence is going as well as you do, your opponent has better things to do than swarm reinforcements behind a piece that is a goner.