Next to orthodox Chess (aka FIDE or Mad Queen), XBoard supports many other Chess variants. This includes the World's major forms of Chess: Chinese, FIDE, Japanese, and Thai Chess. But also many popular western variants (Suicide Chess, Crazyhouse, Chess960, Gothic/Capablanca Chess, Seirawan Chess).
Full support by XBoard means that the latter is fully aware of how all pieces move, and what the winning condition is. This means the variant can be played with the option Test Legality switched on, and that it can accurately check any result claims that engines make. Non-supported variants can often be played with legality checking switched off. Then any of the 22 piece types known by XBoard can be used in ways XBoard does not expect. The only real drawback of this is that the game notation looks a bit crummy, with many spurious or missing disambiguators, check and checkmate symbols. XBoard will always be able to read suh games back, however (as on reading it suffers from the same misconceptions on piece movement). This can be kept baerable by choosing XBoard supported pieces to represent the unsupported ones that move as similar as possible.
Some variants are only partially supported. This means they have to be played with legality checking off, although XBoard knows they exist, and even implements some of their rules that no other variant would allow. For instance, in Berolina Chess Pawns move diagonally, and in any other variant this would lead to disappearence of other Pawns during the game, as normally XBoard interprets a diagonal Pawn move to an empty square as e.p. capture.
The following list tries to group all variants by properties. Some duplicates occur when a variant fits in more than one group.
| = recommended | |
| FIDE Chess | The modern international game, second in popularity only to Xiangqi |
| Shuffle games with normal pieces | |
| Wild Castle | Shuffles the initial FIDE setup, leaving King and Rooks in place |
| No Castle | More aggressive shuffling of the initial FIDE setup, without castling |
| Chess960 | A Shuffle variant where even Kings and Rooks in non-standard location can castle |
| Variants with piece drops | |
| Crazyhouse | Pieces you capture are added to your army, by dropping them back onto the board |
| Bughouse | four-player game that XBoard can only play with the aid of an Internet Chess Server |
| Shogi | Japanese Chess, where pieces you captured can be dropped to strengthen your own army |
| mini-Shogi | Highly simplified and very tactical mini version of Shogi (on 5x5 board) |
| Unusual winning conditions | |
| Suicide Chess | Win by getting rid of all your material by mandatory capture |
| Give-Away Chess | Win by getting rid of all your material by mandatory capture |
| Losers Chess | Win by being left with a bare King |
| 3-checks | Lose by being checked 3 times |
| Variants with various intrusive rules | |
| Atomic Chess | Pieces that capture explode, destroying anything in the vicinity |
| Cylinder Chess | The a-file and h-file connect to make the board a cylinder |
| TwoKings | Play with two Kings, changing which one is royal during the game |
| Variants where just a few pieces move in unorthodox ways | |
| Shatranj | Ancient Arabic/Persian Chess, with primitive Queen and Bishops |
| Berolina Chess | Pawns capture straight ahead, and move diagonally |
| ASEAN | South-East Asian Chess, a modernized version of Makruk |
| Knightmate | Try to checkmate a single Royal Knight with (amongst others) two non-royal Kings |
| Falcon Chess | Two (Rook-class) Falcon pieces augment FIDE on a 10-wide board |
| Mighty-Lion Chess | All-powerful Lions can capture other pieces en-passant, or two pieces at once |
| Variants with extra Rook-Knight and Bishop-Knight compound pieces | |
| Seirawan Chess | Two extra super-pieces can be 'gated' onto the board during the opening |
| Capablanca Chess | Two super-pieces are added to FIDE on a 10-wide board |
| Gothic Chess | Two super-pieces are added to FIDE on a 10-wide board, with stream-lined initial setup |
| Janus Chess | Two Janus super-pieces (B-N compounds) are added to FIDE on a 10-wide board |
| Capablanca Random Chess | Capablanca Chess with shuffled initial setup, with generalized castling rules |
| Grand Chess | Chess on a 10x10 board with two extra super-pieces |
| Oriental forms of Chess | |
| Xiangqi | Chinese Chess, where the King is confined to a Palace |
| Shogi | Japanese Chess, where pieces you captured can be dropped to strengthen your own army |
| Sho Shogi | Ancient precurser of the modern Japanese 9x9 Shogi game (without drops) |
| Chu Shogi | Ancient Japanese Chess with many pieces on a 12x12 board, and a Lion super-piece |
| Makruk | Thai Chess, with an interesting Elephant piece |
| ASEAN | South-East Asian Chess, a modernized version of Makruk |
| Variants with mostly un-orthodox pieces | |
| Courier Chess | Mediaval precursor of Chess, combining Shatranj with modern pieces on a wide board |
| Superchess | Randomly picked unorthodox pieces of many kinds replace some of your FIDE pieces |
| Great Shatranj | Version of Capablanca Chess that replaces all sliding moves by 2-square jumps |
| Spartan Chess | Two different armies (Persians and Spartans, the latter lead by two Kings) battle each other |
| Chess with Different Armies | Pick one of a set of (mostly) unsual armies to battle a completely different army |
| Chu Shogi | Ancient Japanese Chess with many pieces on a 12x12 board, and a Lion super-piece |
| Chu Chess | Intermediate between Chess and Chu shogi, on a 10x10 board |
| Cambodian Chess | |
| Ai-Wok Makruk | |