Special moves
Castling
The king-and-rook move that hides the king and activates a rook.
What is the castling?
Castling is the one move where two pieces move at once: the king steps two squares towards a rook, and the rook hops to the king's other side. It is the fastest way to tuck the king into safety and bring a rook towards the centre.
Why the castling matters
Tactically it cuts both ways. Failing to castle leaves the king in the centre, where most opening disasters happen, and castling itself can be a tactic, whether castling out of a pin or castling to land a rook on an open file with a sudden threat.
How to use it to win
As a rule, castle early and ask questions later: a king in the centre is a target. But always check the in-between: is there a check or capture that exploits the king's trip, or does castling come with gain of tempo?
Try an example puzzle
A real castling puzzle from the app. White to move. Find the idea, then reveal the line.
4 
a b 
e h 1 Show solution
1. O-O#
New to chess? Start with the rule itself: What is castling in chess? · Castling rules: the five conditions
Drill the castling on thousands of real puzzles, matched to your rating.