There are a couple of matters that chess beginners (and even some advanced players) don’t completely understand about the rules for castling; this article should clear up those misconceptions.
Can the King castle if it has been checked?
Some players … usually brand new players … mistakenly believe that if the King has ever been checked, he loses the right to castle. This is not true. In order to lose the privilege of castling, the King must have moved. And by the way, it doesn’t matter if the King moved because it was in check, or just because it felt like taking a stroll. If the King moves, it can no longer castle; but a King that has been checked may still castle – provided it hasn’t moved.
The King might be checked any number of times and still castle, provided that the King has never moved out of check. (Usually checks against the uncastled King are blocked by an interposing piece or the checking piece is captured to preserve the castling privilege.)
How about the Rook?
You remember that the King may not castle out of or “across” check. (Review my previous article on castling.) If the King is in check, he can’t castle out of the check. And if the King must cross a guarded square in castling, again castling is prohibited.
But this rule does not apply to the Rook. A Rook may castle out of an attack. And the Rook may castle “across” a square that is attacked. (This latter case occurs only on Queenside castling, and I explain that in the video.)
In fact, there’s a nifty little trap (a type of double attack) in which you castle long (to the queenside) the Rook crossing an attacked square, delivering check to the opposing King with your Rook, and attacking the enemy Rook with your King. It’s pretty rare, but good to know about! Take a look at the video to see examples.
My next video will be on how the pawn “en passant” capture works.
If you want a great book for beginners that explains the rules and gives a good foundation for understanding basic chess tactics, be sure to get Learn Chess: A Complete Course. Click the link or find it in my chess store.