What is a chess variant?
A chess variant keeps most of chess and changes something important: where the pieces start, what a capture does, how you win, or how many people play.
Chess itself grew out of earlier variants. The game played in the medieval Islamic world, shatranj, had a much weaker queen and bishop; today’s rules only settled in Europe in the late 15th century. Modern variants are mostly deliberate experiments, designed to make the game faster, wilder or less dependent on memorised openings.
They fall into a few families:
- New starting positions: Chess960, Horde, Racing Kings.
- Pieces come back: crazyhouse and bughouse.
- New ways to win: three-check, King of the Hill, atomic, antichess.
- New boards: 3D chess and other shapes and sizes.
- Chess plus something else: such as chess boxing.
Explore 9 chess variants
Pick a variant to see its board and rules. Every position shown was generated and checked in code.
Chess960
BBQNNRKR. Bishops on opposite colours, king between the rooks, Black mirrors White.
The pieces behind the pawns are shuffled before the game, so memorised openings stop working. Everything else is normal chess, apart from how castling is worked out. FIDE includes the rules in its Laws of Chess, and it is also sold as “Freestyle Chess”. The standard set-up is position number 518.
Full guide and a position generator: what is freestyle chess?
Crazyhouse
Each side has captured one pawn. In crazyhouse, each can now drop that pawn onto an empty square instead of moving.
When you capture a piece it joins your reserve. On any later turn you may drop it on an empty square instead of making a normal move. Games are full of sudden mating attacks, because pieces can appear next to the king out of nowhere.
Pawns cannot be dropped on the first or last rank. It is the two-player version of bughouse.
Bughouse
Team 1 plays White here.
Team 1 plays Black here, so each team has one White and one Black.
Four players, two teams, two boards. Partners sit side by side, one with White and one with Black. Whenever you capture a piece, you hand it to your partner, who can drop it on their own board instead of moving. The match ends as soon as either game ends (rules summary).
It is fast, loud and very social, usually played with short time controls. The four-player game was already appearing in U.S. newspapers as “double bughouse” in the early 1970s.
Atomic
The knight on g5 attacks f7, next to Black’s king.
King, bishop f8, knight g8, the f7 pawn and the capturing knight are gone. Pawns e7 and g7 survive. White wins.
When a piece captures, the captured piece, the capturing piece and every piece on the eight squares around the capture are removed. Pawns next to the explosion survive. Blow up the enemy king and you win immediately. A king can never capture, because it would blow itself up.
The example above is a real trap: three moves in, 3.Nxf7 destroys the black king. This was checked by playing the moves with chess.js and applying the explosion rule square by square.
King of the Hill
Bring your king to any of the four marked squares and you win.
Normal chess, plus one extra way to win: walk your king onto one of the four centre squares. Kings, normally kept safely in the corner, suddenly have a reason to march up the board, which turns ordinary positions upside down.
Three-check
3.Bxf7+ is White’s first check. Two more and White wins.
The first player to give check three times wins, even if none of them is checkmate. Every check counts, so king safety matters from move one, and sacrifices that only give a check become real winning tries.
Antichess
White must capture: Bxb5 is the only capture available, so it is the only legal move.
Also called losing chess or giveaway. If you can capture, you must. The king is just an ordinary piece with no check or checkmate, and you win by getting rid of all your pieces. It is a game of forcing your opponent to take things.
Horde
36 white pawns against a full black army.
White’s “horde” of 36 pawns tries to checkmate Black; Black wins by capturing every pawn (and anything they promote to). Pawns on the first rank can also move two squares.
Racing Kings
Both armies start side by side on ranks 1 and 2. Giving check is not allowed.
Both kings race to the eighth rank. Checks are completely forbidden, so you block your opponent’s king with your pieces rather than attacking it. If White gets there first and Black reaches the eighth rank on the very next move, the game is drawn, to offset White moving first.
All variants at a glance
| Variant | What changes | How you win |
|---|---|---|
| Chess960 | Back-rank pieces start in one of 960 shuffled positions | Checkmate |
| Crazyhouse | Captured pieces change sides and can be dropped back on the board | Checkmate |
| Bughouse | Two-against-two on two boards; captures go to your partner | Checkmate on either board |
| Atomic | Every capture causes an explosion that removes nearby pieces | Blow up the enemy king (or checkmate) |
| King of the Hill | Getting your king to the centre also wins | Checkmate, or king reaches d4, d5, e4 or e5 |
| Three-check | Giving three checks wins | Checkmate, or check the enemy king three times |
| Antichess | Captures are compulsory and you try to lose all your pieces | Lose all your pieces, or be stalemated |
| Horde | White has 36 pawns and no pieces; Black has a normal army | White: checkmate. Black: capture every white pawn |
| Racing Kings | No pawns, no checks; race your king to the last rank | First king to the eighth rank |
Rules as published by Lichess (bughouse: Wikipedia). Exact rules can differ between sites and clubs.
What is 3D chess?
3D chess is a family of variants that replace the flat board with a three-dimensional one, usually stacked boards. Pieces can move between levels as well as across them.
Raumschach: the classic 3D game
The oldest 3D game still played is Raumschach (“space chess”), patented by the German Ferdinand Maack in 1907 (Wikipedia). It is played on five stacked 5×5 boards: a cube of 125 cells, about twice the 64 squares of a normal board. Maack first tried an 8×8×8 cube but settled on 5×5×5 as the better game (Chess Variant Pages).
Raumschach adds a new piece, the unicorn, which moves along the cube’s space diagonals, changing rank, file and level at once. That makes it a strangely limited piece. We counted every cell a unicorn can ever reach: depending on where it starts, it is confined to just 30 or 35 of the 125 cells, for the whole game. In normal chess, a bishop is limited to half the board; a unicorn is limited to less than a third.
Counted by exploring every unicorn move from every one of the 125 starting cells.
Star Trek’s Tri-Dimensional Chess
The 3D chess most people picture is the one in Star Trek, which first appeared on screen in the 1960s: three main boards plus small movable “attack boards”. The show never gave full rules, so fans wrote them later; the best known are the rules in Franz Joseph’s Star Fleet Technical Manual and later Standard Rules by Andrew Bartmess (Wikipedia).
Can you play 3D chess?
Yes. Raumschach and Tri-Dimensional Chess both have complete rule sets, physical sets and computer versions, though they are niche hobbies. If you want a taste of chess with an extra dimension of difficulty without the hardware, crazyhouse or atomic are easier places to start.
What does “playing 4D chess” mean?
“4D chess” is mostly an idiom, not a game. Saying someone is “playing 4D chess” means they are making moves so clever and far-sighted that ordinary people can’t follow them. According to Wiktionary, the phrase became popular around 2017 in U.S. politics, and it is usually used ironically: to mock the claim that an obvious blunder is secretly a brilliant plan.
The phrase builds on an older one, “playing three-dimensional chess”, used for complicated strategy. A few hobbyists have designed actual four-dimensional chess games, but none is widely played. The related phrase “playing chess, not checkers” has its own explanation in chess vs checkers.
Relatives of chess and other variants
Chess has cousins that are separate games rather than variants: xiangqi (Chinese chess), shogi (Japanese chess, which also lets you drop captured pieces, like crazyhouse) and makruk (Thai chess). All descend from the same ancient Indian game. Go is often compared with chess but is unrelated; see Go vs chess.
Beyond the nine above, there are thousands of invented variants: bigger boards with new pieces, games for three or four players, hand-and-brain chess (one partner names the piece, the other moves it) and blindfold chess, where nothing about the rules changes but you play without seeing the board.
Which chess variant should you try first?
- You want normal chess without opening theory: Chess960.
- You want fast, attacking games: crazyhouse or three-check.
- You have three friends and a loud room: bughouse.
- You want something completely different: atomic or antichess.
- You want to improve at normal chess: King of the Hill and three-check reward the same king-safety skills as standard chess. For standard practice, play against Stockfish.
FAQ
What are chess variants?
Games that change one or more rules of standard chess: the starting position, how pieces move, how you win or how many people play. Popular examples are Chess960, crazyhouse, bughouse, atomic, three-check and King of the Hill.
What is the most popular chess variant?
Chess960 (Fischer Random, or Freestyle Chess) is the most established: it is part of FIDE’s Laws of Chess and has official FIDE events. Online, fast variants like crazyhouse and atomic also have dedicated followings.
What is atomic chess?
A variant where every capture causes an explosion that removes the captured piece, the capturing piece and all non-pawn pieces next to it. You win by blowing up the enemy king.
What is bughouse chess?
A four-player team game on two boards. Partners play opposite colours, and every piece you capture is passed to your partner, who can drop it onto their board.
What is 3D chess?
Any chess variant played on a three-dimensional board. The classic version is Raumschach (1907), played on a 5×5×5 cube with 125 cells; the most famous is the Tri-Dimensional Chess seen in Star Trek.
Is 3D chess real?
Yes. Several playable 3D variants exist, including Raumschach and rule sets written for the Star Trek board. Star Trek itself never gave complete rules; fans wrote them later.
What does “playing 4D chess” mean?
It is an idiom for making moves so clever and far-sighted that others can’t follow them. It is often used ironically, to mock someone whose supporters claim there is a hidden master plan.
What is crazyhouse?
A two-player variant where captured pieces join your side and can be dropped back onto any empty square instead of making a normal move.
Where can I play chess variants?
Lichess offers Chess960, crazyhouse, King of the Hill, three-check, antichess, atomic, horde and racing kings for free. Many other sites and apps offer some of them.
Sources and how we checked
- Lichess variant rules: Chess960, crazyhouse, atomic, King of the Hill, three-check, antichess, horde, racing kings.
- Bughouse chess and Three-dimensional chess, Wikipedia; Raumschach, The Chess Variant Pages; “4D chess”, Wiktionary.
- FIDE, Laws of Chess (Chess960 guidelines).
- How we checked: Chess960 position 0 and the 960-position count from the Scharnagl numbering; crazyhouse, three-check and antichess examples played out with chess.js 1.4.0 (the antichess example is checked to have exactly one capture); the atomic explosion applied square by square; Horde pawns and Racing Kings set-up counted, and both kings checked not to be in check; Raumschach unicorn regions counted from all 125 cells.