Castling in Chess: Everything You Need to Know


castling in chess
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Castling is one of those special rules where to be a strong player you don’t just need to know how to castle in chess, you need to master how to castle in chess!

Thankfully, castling is not too hard to get to grips with but once you know the basic rules there are a few pointers you need to be aware of.

In this quick guide, we’ll tell you everything you need to know about castling, answer all the questions that often crop up and give you some exciting examples of games where castling made the difference. And there’s even a quick puzzle to solve to check you’re paying attention.

What is castling in chess?

Castling is one of those special moves in chess that you need to know to play properly. It is the only time you get to move two pieces at the same time and each player is only allowed to castle once, under certain conditions.

The move is crucial, but it is also simple to learn. There are two types:

King-side castling – where the White king goes two spaces to his right, and on the other side of the board the Black king can go two spaces to his left. See this diagram with the kings moving along the red line and the rooks along the green line:

How to castle in chess: King-side castling
King-side castling

Queen-side castling – similar in that the king moves two spaces but this time the White king goes left and the Black king goes right. See here:

How to castle in chess: Queen-side castling
Queen-side castling

In both cases, the rook jumps over the king and settles next to him. One thing to remember is that if you want to castle you need to pick up the king first – not the rook. This is very important!

The final positions should look like this if White castled queen-side and Black castled king-side:

White has castled queen-side and Black castled king-side

But in short, if someone asks you how to castle in chess just say it is when the king moves two spaces to his left or to his right and the rook jumps over him and ends up on the other side.

However, as always there are a number of conditions that must be met to make it a legal move or it won’t be allowed and your opponent will say “hang on a minute!” But we will get onto the nitty-gritty a bit later on and answer a few questions first.

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Why castle in chess?

Castling is primarily all about getting your king safe because, usually, the move takes your most important piece out of the center of the board and tucks him away behind a wall of pawns.

Games are won and lost by players deciding if and when a player to castle. In fact, when it comes to beginners a very high proportion of games are lost simply because a novice player doesn’t get their king protected. So it pays to castle.

But beware, the timing is crucial – sometimes castling may actually put your king in danger. So, as with everything in chess, be careful.

It is for this reason that while beginners are often taught to castle as soon as they can, you often see experts put off castling until much further into the games.

Let me repeat the point: timing is crucial.

This video is from The Art of Attack in Chess Course

What does castling achieve in chess?

Castling does two things: 1. it creates a safe haven for your king (or should, if you do play it at the right time) and, 2. it develops your rook, bringing it out nearer to the center of the board where it can get into the game.

Castling, therefore, is a very nifty maneuver. But like every move in chess, you have to judge when the right time to play it is.

Here’s a good example of a classic game where castling at the right time was crucial. Scroll through it and see how powerful White’s castling proved:

A quick puzzle – what happens if Black castles here?

This puzzle is taken from GM Susan Polgar’s Learn Chess The Right Way series for beginners.

It is Black to move:

Taken from GM Susan Polgar's Learn Chess The Right Way series

In order to be allowed to castle, neither the king nor the rook (on a8) could have moved at any time earlier in the game.

This rarely happens in a regular game as it is generally advisable to castle in the early part of the game. Black checkmates by castling queenside (king to c8 and rook jumps over it to d8).

Here is another example of a real-life game played in London, 1912, in which checkmate by castling could have occurred, but the winner decided to play Kd2 instead:

How to castle in chess – the rules

Remember what we said before about the king moving two spaces to the left or right and the rook jumping over? That is how you make the move on a basic level, but we also said there are a number of rules that apply to make it legal.

Castling can only happen if all of the following conditions are met in a game:

  1. The king has not previously moved;
  2. Your chosen rook has not previously moved;
  3. There must be no pieces between the king and the chosen rook;
  4. The king is not currently in check;
  5. Your king must not pass through a square that is under attack by enemy pieces;
  6. The king must not end up in check.
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But the idea of castling – or not, as the case may be – should be on your mind right from the first move. Don’t wait for those conditions to arise out of the opening – work to make them happen if you want to castle. And most of the time you probably will.

Remember for most players at beginner/intermediate levels there are three basic aims you should be trying to achieve in the opening. They are:

  1. Occupy the center
  2. Develop your pieces
  3. Get your king safe/castle

So you can see that understanding castling and when to effect it should be a fundamental part of your training.

OK, I know how to castle in chess – but not when?

Now you know how to castle in chess, your king’s safety should always be on your mind. You should always consider castling if you want a safe king and are able to. However, there are points where it may be a bad idea.

One example of when castling may be a bad idea is if your king is already safe and it is a waste of time and put it off.

The reason for this is that at the start of the game, during the opening, developing your pieces is equally if not more important. It is hard for the opposition to directly threaten your king’s safety early on and if they don’t play any threatening moves then you may feel getting your pieces out and launching your own attack is more important.

In many ways, chess is like a race where you have to get your big guns out quickly if you want to hurt the opposition. Attack is sometimes the best form of defense.

The other consideration to make is whether, as we discussed before, you are putting your king in jeopardy. Opposite-side castling, that’s when one player castles king-side and the other goes queen-side, can often be a bit dodgy. Positions, where that has happened, tend to be very double-edged and benefit one player over the other. If that is you, then great, if not – be wary.

What is the code for castling on the king’s side in standard chess game notation?

A quick and easy answer here: 0-0 is the code for castling on the king’s side in standard chess game notation. And 0-0-0 is the code for castling on the queen’s side in standard chess notation.

When the castle comes crashing down! A famous game to enjoy

In this brilliant game from way back in 1862, the great Adolf Anderssen playing Black shows how to punish White for castling queen-side. White, played by Jakob Rosanes, failed to castle early and then got into trouble as Black’s pieces launched an attack.

On move 14 he castled queen-side (0-0-0 in chess notation) as a way to get his king safe and protect White’s double threat against the b2 pawn and the knight on g1. It didn’t help, scroll through this to see what happens:

Castling FAQs answered

What are the four rules for castling in chess?

We’ve tried to give a fuller explanation above, but the rules of castling are often boiled down to four points so they are easy to remember. Here they are:

  1. The king and the rook may not have moved from their starting squares if you want to castle.
  2. All spaces between the king and the rook must be empty.
  3. The king cannot be in check.
  4. The squares that the king passes over must not be under attack, nor the square where it lands on.

Is castling a good move in chess?

In the right circumstances, yes. Thankfully, those circumstances occur quite often so generally, it is a good move. But watch out! It can be a shocker!

Can you castle out of Checkmate?

No. Remember the golden rules above: you can’t castle through a line of check. Besides, it wouldn’t be checkmate if you could castle out of it, checkmate only occurs when it is the end of the game.

What is the advantage of castling in chess?

King-safety and developing your rook, which gets to pop out into the open and affect the game.

How many times castling can be done in chess?

Each side only gets to castle once in a game.

When was castling added to chess?

Castling was a relatively late addition to this 1,500-year-old game. It was only introduced around the 14th or 15th century and did not develop into its present form until the 17th century.

Can you Castle your queen?

No, don’t be silly. We haven’t mentioned the queen at all in this guide.

Can you castle if you have been in check?

If you have previously been in check, but are no longer, then yes.

What is the advantage of castling in chess?

Usually, it’s getting your king into a nice, safe cubby-hole and getting the rook out to attack.

Can you castle if Rook is under attack?

Yes, it’s only the king you have to worry about.

When was castling added to chess?

Same answer as above – in the 14th or 15th century.

Why is Castle called Rook?

It is believed to come from the Persian word “rukh”, meaning chariot. There are many theories as to how the present version was arrived at, but one possible explanation is that when the game was imported to Italy, the Persian rokh became the Italian word rocca, meaning fortress.

Can you castle through a knight?

Through a knight’s check? No. Over a knight? No.

Can you castle on the queen side in chess?

Yes the king can castle both sides. See above for how.

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