We’ll leave the relative pin for a future post. Let’s consider now the absolute pin.
The above position is taken from the new book Beat That Kid in Chess (page 13).
Notice that the white queen and bishop are lined up, pointing along that diagonal towards the black pawn that is directly in front of the black king. With white to move, checkmate is possible, by the white queen capturing that pawn . . . except for one thing: It’s illegal.
The black queen is pinning the white queen. In this case, it prevents the white queen from any move except along the other diagonal, the one leading from the white king to the black queen. Why? One cannot expose one’s king to check, NOT EVER. And yet it’s perfectly legal for the white queen to capture the black queen. In fact, I would advice it in this position, for the resulting simple endgame should be a win for white.
A pin often is a disadvantage to the side having the pinned piece, but not always. Consider now the position below:
From page 18 of Beat That Kid in Chess
Notice a similar pin to the previous one: The white queen cannot move off the line-of-fire leading from the black bishop to the white king. Also like the previous diagram, the white queen can capture the pinning piece. Yet the result is immediate checkmate: Qxb8 mate.
Absolute pins involve a king, preventing the pinned piece from moving off the line of attack against that king. Some absolute pins are infinitely restrictive, preventing the pinned piece from any movement. In the above position, change the white queen to a white rook and notice that the rook would have no legal move whatsoever.
Notice also that a knight cannot make a pin although it can itself be pinned.
Let’s begin this kind of endgame study with defense: How do you draw when you have only a rook and king and your opponent has only a queen and king?
There are two kinds of pins in chess: the relative pin, and the absolute pin.
Most chess battles, tactics and attacks, come in the middle game. If you’re a beginner, looking ahead is a skill worth learning.
In the above position, the pawn can be promoted regardless of whose turn it is. This key position has the attacking king in front of its pawn, with only two squares in front of that king.