Variant Library
Moddable Chess includes 153 playable variants spanning classic rules, asymmetric battles, hidden information, expanded boards, and alternative win conditions. Each variant has its own complete rules page.
Standard Board (8x8)
- Standard Chess – Classic FIDE rules
- Absorption Chess – Capturing piece gains the victim’s movement permanently
- Andernach Chess – Capturing piece changes colour
- Anti-King Chess II – Each player adds a royal Anti-King that is in check when NOT attacked
- Atomic – Captures explode adjacent pieces
- Avalanche Chess – After each move, push one of the opponent’s pawns one square forward
- Benedict Chess – Attacked enemies convert colour
- Berserk Chess – Check grants a bonus move
- Checkless Chess – No check unless it is checkmate
- Crazyhouse – Captured pieces switch sides and drop back onto the board
- Cylinder Chess – Files wrap, a-file connects to h-file
- Dark Chess – Only see squares your pieces occupy
- Dice Chess – Die roll constrains piece type
- Displacement Chess – Swap positions with adjacent friendly pieces
- Duck Chess – Place a blocker duck after each move
- Einstein Chess – Captures promote pieces, non-captures demote them
- Extinction Chess – Lose when any piece type is eliminated
- Fischer Random – 960 randomised starting positions
- Fog of War – Only see squares your pieces attack
- Grid Chess – Moves must cross a 2x2 grid line
- Hoppel-Poppel – Knights capture like bishops, bishops capture like knights
- Horde Chess – 36 pawns vs a normal army
- Immunization Chess – Captures make adjacent enemies immune for 2 turns
- King of the Hill – King reaches centre = instant win
- Madrasi Chess – Same-type opposing pieces paralyse each other
- Maharaja & Sepoys – One super-piece vs a full army
- Marseillais – Two moves per turn
- Medusa Chess – Queen petrifies enemy pieces she attacks
- No Castling – Standard chess, castling disabled
- No Retreat – Pieces cannot move backward
- Patrol Chess – Capture only when defended by a friendly piece
- Poison Chess – Capture squares become poisoned for 3 turns
- Racing Kings – No checks allowed, race King to rank 8
- Recruitment Chess – Captured pieces defect to the captor
- Rifle Chess – Capturing pieces stay on their square
- Teleport Chess – 3 teleports per game to any empty square
- Torpedo Chess – Pawns can always double-move
- Toroidal Chess – Board wraps in both directions forming a torus
- Weak! – Weakest piece type must move first
Multi-Move Variants
- Monster Chess – White gets 2 moves, Black gets 1
- Progressive – Escalating moves per turn (1, 2, 3, 4…)
Alternative Win Conditions
- Antichess – Forced captures, lose all pieces to win
- Chak – 9x9 Mesoamerican chess; move your Warrior Ajaw to the opponent’s temple and survive
- Chennis – 7x7; advance a Pawn to the opponent’s back rank to win (no checkmate)
- Codrus – Lose your King to win, no check concept
- Five-Check – Five checks to win
- Giveaway – Forced captures, lose all pieces to win (stalemate = loss)
- Omnicide – Lose all pieces to win, captures NOT forced
- Single-Check – One check wins instantly
- Stalemate Wins – Stalemating your opponent wins
- Suicide Chess – Forced captures, lose all pieces to win (stalemate = draw)
- Three-Check – Deliver three checks to win
- Ultima – Seven unique capture methods; win by capturing the opponent’s King
Asymmetric Armies
- Empire Chess – FIDE Kingdom vs Empire; Empire pieces all move as Queen but capture piece-specifically; faceoff rule
- Khan’s Chess – FIDE Kingdom vs Mongol Horde with Scout and Khatun; divergent pieces; campmate and stalemate-loss
- Orda Chess – FIDE vs divergent Horde army; all Horde pieces move as Knight
- Shinobi Chess – FIDE vs Shinobi Clan; hand drops; automatic zone promotion
- Shinobi+ – Rebalanced Shinobi with Fox piece; Clan moves first; perpetual check is a loss
- Spartan Chess – FIDE vs Spartan army with two Kings; dual-check rule
- Synochess – FIDE Kingdom vs Xiangqi-derived Eastern dynasty; Cannon, Chariot, Horse; faceoff rule
Gating & Drop Mechanics
- Dragon Chess – Two Archbishops held in reserve; gate onto any empty first-rank square instead of moving
- Hostage Chess – Captured pieces become hostages; rescue yours by releasing one of theirs
- Mansindam – 9×9 board; compound pieces (Cardinal, Marshal, Angel); Shogi-style drops + mandatory promotion; campmate; no draws
- Pocket Knight Chess – One extra Knight in reserve; drop it onto any empty square once per game
- S-Chess – Hawk and Elephant held in hand; gate onto vacated home squares when back-rank pieces move
- Shogun Chess – Shogi-style drops; captured pieces switch sides; promotion on ranks 6-8
- Xiang Fu – Xiangqi/chess hybrid; dual royal Champions, Crossbow piece, drops within first two ranks
Piece Replacement & Movement Variants
- Alice Chess – Two boards; pieces transfer between boards after each move
- Almost Chess – One queen replaced by Chancellor (R+N)
- Amazon Chess – Queens replaced by Amazons (Q+N)
- Berolina Chess – Pawns move diagonally and capture straight (inverted)
- Chigorin – White has 4 knights instead of bishops
- Fanorona Chess – Captures by approach and withdrawal on a 5x9 Alquerque board
- Grasshopper Chess – Hoppers replace Queens; must jump over a hurdle to land
- Knightmate – Knight is royal, King moves like a knight
- Nightrider Chess – Knights replaced by Nightriders; repeat Knight-moves in one direction
- Orda Mirror – Both sides Horde army; all pieces move as Knight, capture as FIDE counterpart
- Wildebeest Chess – Camel and Wildebeest (N+Camel) added to a 10x11 board
Starting Position Variants
- Endgame Chess – Only pawns and Kings from the start
- Legan Chess – Berolina pawns, King and Queen swap starting squares
- Pawns Only – Only pawns, first promotion wins
- Peasants’ Revolt – King + pawns vs King + knights
- Placement Chess – Back-rank pieces placed during a setup phase before play begins
- Upside-Down – Pieces start on opponent’s rank
Regional & Historical Variants
- ASEAN Chess – Standardised Makruk; pawns on rank 2, streamlined counting rules
- Chaturanga – Indian ancestor of chess, c. 600 CE. Weak counsellor and leaping elephant.
- Makpong – Thai variant, King cannot move out of check
- Makruk – Thai chess, pawns promote on rank 6 to Met
- Ouk Chaktrang – Cambodian chess; Koul leaps 1-2 diagonally; King may jump as Knight on first move
- Senterej – Ethiopian Shatranj; simultaneous mobilization phase before the first capture
- Shatar – Mongolian chess, win by baring the opponent’s King
- Shatranj – Medieval Islamic chess, ancestor of modern chess
- Sittuyin – Burmese chess, placement opening phase
- Tamerlane Chess – 11x10 board with citadels; 12 piece types; complex pawn promotion system
Expanded Boards
- Archchess – 10x10 variant (1683); adds Centurion and Decurion pieces
- Bird’s Chess – 10x8 board (1874); adds Guard (R+N) and Equerry (B+N)
- Capablanca Chess – 10x8 with Archbishop + Chancellor
- Carrera’s Chess – 10x8 board (1617); adds Champion (R+N) and Centaur (B+N)
- Chancellor Chess – 9x9 board (1889); adds one Chancellor (R+N) per side
- Courier Chess – 12x8, medieval variant from 1202
- Grand Chess – 10x10, same new pieces, bigger stage
- Gustav III’s Chess – 8x8 + 4 corner squares; adds 2 Amazons (Q+N) per side
- Gygax Chess – Three stacked 12x8 boards; 42 pieces per side across 15 piece types
- Janus Chess – 10x8 with two Januses (Archbishop: B+N) per side
- Omega Chess – 10x10 + 4 wizard squares; adds Champion and Wizard
- Shako – 10x10; adds Cannon (platform capture) and Elephant (2-diagonal leap)
Small Boards
- Breakthrough – 7x7, pawns only, first to far rank wins
- Congo – 7x7 with river; six animal piece types; capture the Lion to win
- Crazy 38’s – 38-square loop board; Shogi-style drops; checkmate or reach opponent’s Home Square
- Diana Chess – 6x6, no queens or knights
- Flip Chess – 38-square board; bare King loses immediately
- Half Chess – 8x4, armies start adjacent
- Hexapawn – 3x3 pawn-only game (Gardner, 1962); solved: Black wins with perfect play
- Hole Chess – 44-square board with permanent holes that suck in enemy pieces
- Los Alamos – 6x6, no bishops, first computer chess (1956)
- Minichess – 5x5, full piece types on tiny board
- Petty Chess – 5x6, all piece types, single copies
- Rollerball – 40-square ring board; clockwise-dominant movement; King race wins
Hexagonal Board
- Brusky’s Hexagonal Chess – 84-hex irregular board, 10 files
- De Vasa’s Hexagonal Chess – 81-hex rhombus (9x9), pawns start on rank 3
- Gliński’s Hexagonal Chess – 91-hex board, the most widely played hex chess variant
- McCooey’s Hexagonal Chess – 91-hex board, bishops start on same colour
- Mini Hexchess – Compact 37-hex board, one of each piece type
- Shafran’s Hexagonal Chess – 70-hex board, 9 files (a-i)
Topology Variants
- Byzantine Chess – Circular 4-ring board (64 squares); Shatranj-era pieces; stalemate wins
- Circular Chess – 4 rings x 16 files; pawns promote after 6 squares; no null moves
- Cylindrical Chess – Files wrap (a connects to h); bishops and queens gain power
- Klein Bottle Chess – Non-orientable surface; ranks wrap with a half-twist mirroring files
- Möbius Strip Chess – Non-orientable strip; rank seam twists; bishops change colour at seam
- Spherical Chess – Ranks wrap horizontally; files meet at polar singularities
- Toroidal Byzantine Chess – 4-ring circular board with radial wrap forming a torus
Large Historical
- Balbo’s Chess – Diamond-shaped 70-square board (1974); location-dependent promotion
- Centennial Chess – 10x10 with 4 new pieces; two moves per turn until first capture
- Citadel Chess – 10x10 + 4 citadels; Shatranj al-Husun; King in citadel forces a draw
- Grande Acedrex – 12x12 medieval Spanish variant (Alfonso X, 1283); six unique piece types
- Metamachy – 12x12 with 12 piece types; variable starting position for royals
- Oblong Chess – 4x16 historical Shatranj variant; extreme board shifts piece values
- Romanchenko’s Chess – Modified 8x8 with broken columns; pedagogical tool against memorization
- Shatranj Kamil – 10x10 ‘Complete Chess’; adds War Machines immune to check
- Turkish Great Chess II – 10x10; Prince (R+B+N), Kotwal (B+N), and Urdabegini pieces
- Turkish Great Chess III – 12x12; expanded Shatranj with Chariot and Dahja pieces
- Turkish Great Chess IV – 14x14; mixed Indian-Persian origin; weak Queen may be left en prise
3D Chess
- Raumschach – 5x5x5 three-dimensional chess; adds Unicorn (triagonal slider)
Multiplayer (3-4 Players)
- Djambi – 9x9 four-player; corpses block movement; Maze centre grants power
- Four-Handed Chess (Chaturaji) – 8x8 four-player dice chess; points-based scoring, no checkmate
- Los Alamos Vierschach – 84-square cross board; 4-player Los Alamos format with allied teams
- San-kwo-k’i – Three-player Chinese chess representing the Three Kingdoms (220-280 CE)
- Tandem Chess – Two boards, 4 players; captured pieces passed to partner for drops
- Vierschach – German 4-player chess (Lutze); 160-square cross board; allied teams
- Yalta Chess – 3-player on a circular Y-trisection board; captured armies absorbed
Hidden Information
- Blind Chess (Banqi) – Chinese hidden-piece game on 4x8 board; all pieces start face-down
- Kriegspiel – Fog-of-war chess; referee announces partial information about moves
Bughouse & Team
- Delirious Bughouse – Bughouse with dice, worst-move mechanic, and fairy pieces
- Stupidhouse – Bughouse where dropped pieces land on random squares