Do you know what's a half-pin in chess?

Hello Everyone,

We all know what's a pin: When a piece cannot move because it is shielding a piece of greater value behind it.

But do you know what's a half-pin in chess?

It is a situation in which two pieces of the same color are so placed on a file or rank that if either were moved off the line then the other would get pinned. The term was invented by Mansfield in 1915 and is mostly used by composers although half-pins are not unusual in play. Here is an example. There is a half-pin on the a5-e1 diagonal.

From Alexandra Kosteniuk's

www.chessblog.com

Also see her personal blog at

www.chessqueen.com