Think Beyond the Board
4D Chess
Explore four-dimensional chess on a 4 × 4 × 2 × 2 board. Learn how familiar pieces move across spatial axes, then open a free game in your browser.
No download or sign-up · 4D: local two-player or practice computer
Explore 5D Time Travel
Choose Your Game
Different dimensions. Different ways to play.
Explore spatial 4D chess, familiar chess in 3D, or branching histories in 5D.
A fourth dimension to explore.
Move through X, Y, Z, and W on a compact 4 × 4 × 2 × 2 board. View the same game as a hypercube projection or four 3D board slices.
Classic chess. A little more depth.
Play the familiar 8 × 8 game in 3D. Choose local two-player, a practice computer or Stockfish, then explore candidate moves with local analysis.
- f3 · The Departing Knight
White plays g1–f3 and Black replies g8–f6. On White’s next turn, that knight jumps one turn back and two files across to d3.
- d3 · Arrival in the Past
Adding the traveler to the starting position at T1 creates a new branch, with Black to move. Existing history stays unchanged.
- g1 · The Same Knight, Earlier
At that moment it has not left g1, so its past counterpart remains. Together with the other knight on b1, the branch has 3 white knights.
New branch: 33 pieces, including 3 white knights. The original line advances with 31 pieces and f3 empty; the two upper boards remain as historical snapshots. T = turn; L = timeline.
Beyond Spatial Dimensions
Experimental5D Chess With Time Travel
Start on a familiar 8 × 8 board, then move between moments and timelines. A move into the past opens a new branch while the original history stays intact.
What makes it different from 4D chess? The 4D game explores four spatial axes in one position. In 5D, time and timelines become part of the move: you may need to advance several boards before submitting your turn.
Local two-player on one device. Experimental rules; compatibility with the commercial original is still under review.
Plan Across Timelines
Follow the timeline map, preview a cross-board destination, and check the whole turn before you commit. Kings in earlier positions still matter, so a safe-looking move on one board may leave another king exposed.
Learn One Move at a Time
Five guided exercises introduce ordinary moves, travel into the past, cross-timeline play, multi-board turns, and historical king safety. Start with a short lesson, then try a fresh 32-piece game with someone sharing your device.
Return to Your Game
Games and turn drafts save on this device. Undo a draft or complete turn, revisit a game in replay, and export a JSON backup. Check that saving has finished before closing the page or changing language.
Learn the Rules
New dimensions. Clear rules.
See how the coordinates fit together, follow a move across layers, and learn what changes for each piece. W is another direction in space; every move belongs to the same game.
Understand Your Next Move
Before your first 4D game
Get a feel for the board, choose how to play, and follow the links when you need a complete rule or example.
What is 4D chess?
4D chess gives each square four spatial coordinates: X, Y, Z, and W. Familiar pieces move within and between board slices, with checkmate as the goal. This playable variant uses one shared position; W is a spatial direction, and moves do not create alternate timelines.
Understand this 4D variantRead the 4 × 4 × 2 × 2 board
The 4 × 4 × 2 × 2 board has 64 squares, arranged as four 4 × 4 slices. X and Y identify a square inside a slice, while Z and W identify the slice. Compare the labels and highlighted destinations to see how a move crosses dimensions.
Read the coordinate examplesChoose 20 or 32 starting pieces
New players start with the exploration army: 20 pieces, 10 per side, to learn 4D moves. Choose the battle army for 32 pieces, 16 per side, and cross-dimensional combat from the opening. Saved army preferences are preserved. Both use the same rules and keep separate games while the site stays open.
Compare the starting armiesHow the pieces move
A rook follows one axis, a bishop changes two axes equally, and a knight jumps two steps along one axis and one along another. Other pieces have their own four-dimensional paths. Legal-move hints also check whether your king remains safe, so use them before choosing a destination.
Read every piece’s rulesStart your first game
Open the 4D room, choose local two-player mode or the practice computer, and select a white piece to begin. Click a highlighted destination to move. The flat board and spatial projection update together, so you can inspect the same move from both views.
Open the 4D board2D and 3D views, one ruleset
In a 4D game, the projection and 3D board are different views of the same four-dimensional position. The separate 3D Chess page instead plays standard 8 × 8 chess, including castling and en passant. Choose the game first; rotating the camera only changes what you see.
Try standard chess in 3DPractice with a computer
In 4D chess, a local practice computer plays Black using the same four-dimensional rules. The separate 3D chess page also offers Stockfish for standard chess and an analysis panel for exploring candidate moves. Both run in your browser; local two-player mode remains available without an account.
See opponent and game controlsSave a game and return later
4D games can be restored after saving on this device, exported as JSON backups, or manually saved to an account for another device. 5D has its own local saves and backups. Standard 3D chess currently lasts only for the open page session. See the 4D guide for the save and restore steps.
How to save and restore 4D games