Chess Basics: Castling
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Chess Basics: Castling
In a previous lesson, we learned the definitions of check and checkmate and how these concepts are applied in a chess game. To avoid an early loss, new chess players should aim to protect their king as soon as possible. A special move called castling can help secure his safety.
Castling is the only time a king gets to move more than one square at once, and it's the only occasion when a player can move two pieces in the same turn. Let’s walk through how, why, and when to castle, as well as some of the special rules around it.
How to Castle a King
A player can castle their king on either side of the board. The first step to castling is to move any pieces between the king and the rook he’s going to castle with out of the way. Castling cannot take place until there’s a clear path between the king and the rook:
Once this path has opened up, the king will move two spaces towards the rook, and the rook will jump over the king and land on the square next to him:
That's it! The king has successfully castled. This same process applies when the king castles to his left, though the end result looks slightly different:
Why to Castle
The main goal of castling is to protect the king from danger by using the helper pieces–the rook and the three pawns that make up the castle “roof”–as a shield. This makes it harder for enemy pieces to check or checkmate him.
Kings left standing in the middle of the board are often vulnerable to attacks, which can cause players to spend much of the game getting out of danger instead of moving offensively. With their king safely tucked away, players can focus on attacking their opponent’s pieces rather than evading capture.
When to Castle
A good rule of thumb for beginners is to try to castle as soon as possible, usually within the first 10 moves. The longer a player waits to castle, the higher the likelihood something will happen that prevents them from castling.
The Rules of Castling
While castling is allowed at any point in the game, there are four circumstances under which a player cannot castle.
Rule #1: No Moving the King or Rook
Castling must be the first time the king and the rook have moved. If either of them have moved, you can’t use them to castle.
In the position above, White will not be able to castle to his right since the rook has moved off of its starting square. Thankfully, the rook to the left hasn’t moved yet, so White can still castle in that direction.
For new players, most of the trouble with this rule comes from moving the king. To avoid this, beginners should try to deal with early checks by blocking or capturing instead of having the king run away.
Rule #2: No Castling To Get Out of Check
The black queen has the white king in check. When a player is in check, they have to escape the check immediately by using one of the ABCs: running away, blocking, or capturing. Castling is not a legal way of getting out of check.
Rule #3: No Castling Into Check
It's against the rules for a player to put their own king into check. Let’s look at this position:
The white king is safe right now, but if he was to castle to his right, the bishop would place him in check. Instead, White will need to either drive the bishop away, block it to enable castling, or castle on the other side of the board once the path has been cleared.
Rule #4: No Castling Through a Check
Black’s bishop is staring down its diagonal to the square beside the king. If White’s king tries to castle to his right, he’ll have to cross that dangerous square, where he’ll briefly come under attack by the black bishop. A player is never allowed to put their own king in check, even for a moment--this is called passing through a check, and it's against the rules.
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