How To Castle In Fischer Random Chess (Chess960)
Don't know how to castle in Fischer Random? Read through the rules before the 2019 World Fischer Random Championship kicks off this fall!

How To Castle In Fischer Random Chess (Chess960)‎

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The 2019 World Fischer Random Chess Championship quarterfinals are here, with star players like Fabiano Caruana (@FabianoCaruana), Hikaru Nakamura (@Hikaru) and Alireza Firouzja (@Firouzja2003) set to take on five other elite grandmasters.

Of those eight players, three will advance to the World Championship Semifinal in Oslo, Norway, where they will be joined by the reigning world champion Magnus Carlsen (@MagnusCarlsen).

Magnus Carlsen
Magnus Carlsen beat Hikaru Nakamura in their Fischer Random match in 2018. Who will challenge him for the title this year?

While fans might be excited to watch the action, there is a question many seem to have: How do you castle?

Given the hundreds of potential starting positions, identifying themes can be difficult, even for extremely talented players.

Standard Castling Rules

Fischer Random castling rules are built on the established castling rules from classical chess. Just as a quick refresher, those four rules are:

1. The king and castling rook cannot have moved before castling.

2. The king cannot castle out of check/checkmate.

3. The king cannot castle through check.

4. The pieces in between the king and rook must move out of the way before castling.

Want to review castling in greater detail? Visit our extensive guide here to master the technique.

Starting Position Rules

Even though Fischer Random feels like a different type of chess, these core rules hold and are important to remember while considering castling. Like classical chess, Fischer Random makes castling on both the kingside (White's "right") and queenside ("left") of the board possible by mandating that the king's starting position is in between both of the rooks. This means that from the start of the game, both sides will have a designated rook to castle kingside (green) and queenside (blue) with:

No matter how the pieces are arranged (only kings and rooks shown here), the rook closest to the h-file is always used for kingside castling, and the rook closest to the a-file is for castling queenside.

Regardless of the starting position, Fischer Random rules stipulate that the final placement for both the king and rook when castling is constant. This means that if White wants to castle kingside, the king must land on the g1 square, and the kingside rook must land on f1. Should White want to castle queenside, the king must land on c1, and the queenside rook lands on d1. To remember this, think about classical chess castling and where the pieces land:

To castle on Chess.com, you can simply drag the king over the desired rook to complete the move. I

It's worth noting that sometimes the rook may not need to move from the square it is on to castle successfully, and other times, the king and rook may just switch squares. The Chess.com staffer Isaac Steincamp (@IsaacSteincamp) had both of these things happen in the same non-titled qualifier game last June:

In even rarer cases, the king may not even move to castle. This can occur if the king's starting square is on either the g- or c-files, as it is already the final destination for a king to castle:

Note that with the king traveling potentially longer distances than classical chess to castle, it is important to remember that the king cannot castle through check for it to be deemed legal.

Piece Obstruction

Fischer Random also maintains the classical chess rule on piece obstruction preventing castling. Just like classical chess, pieces that obstruct castling by standing between the king and rook moved.

Given the randomness of the starting position, this can directly affect the opening phases of the game. For example, when the center opened in Jose Eduardo Martinez Alcantara 's(@jospem) game with Wesley So (@GMWSO), he quickly developed all of his pieces so his king could jump from d1 to g1:

Fischer Random rules also stipulate that pieces occupying squares that are necessary for the king and rook to castle must also move before castling. This means that if White wanted to castle queenside, both the c1 and d1 squares need to be cleared first—even if those squares are not directly in between the king and rook. The quarterfinalist Vidit Gujrathi (@viditchess) demonstrated this in his tiebreak match against Matthias Bluebaum (@msb2) in the knockout qualifiers last August:

Castling To Safety

If you remember these rules, you should be fully ready to watch the Fischer Random World Chess Championship Quarterfinals this October 4-6.

While castling may not feel as intuitive in Fischer Random, the ability to move to the king to safety quickly can make the difference in any game. One could argue that the quarterfinalist Vladimir Fedoseev (@Bigfish1995) advanced from the knockout stage by doing exactly that:

You can watch the entire Fischer Random World Chess Championship quarterfinals starting at 7 a.m. PT on October 4 on Twitch.tv/chess or Chess.com/tv. To learn more about the event, visit FRchess.com for the tournament schedule, news, and results.

Sometimes the world's best chess players use castling in Fischer Random as an attacking move. Here's a game where Alexander Grischuk castled, and Magnus Carlsen resigned!

Want to learn more about how to play Fischer Random in Live Chess? Visit our guide here.

Fischer Random Quarterfinals Players

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