Play chess against the computer ▶ Play now — Stockfish runs in your browser
Guide updated October 2026 · Runs via WebAssembly (native port)
A chess board and an opponent that never gets tired of you. The computer is Stockfish 19, the strongest open-source chess engine there is, compiled to WebAssembly and running inside this page. You choose how hard it plays: level 1 picks loose moves and looks only one move ahead, level 8 thinks for a second and a half at full strength. Drag a piece or tap it and then a square; the board shows where it can go.
Controls — what does what
| Action | Keyboard | Mouse / touch |
|---|---|---|
| Move a piece | — | Drag it, or click it then click the square |
| Promote a pawn | Esc cancels | Pick a piece from the overlay |
| Take back a move | — | Undo |
FREE This is the complete game, free. Open source: Stockfish (GPL-3.0), chessground (GPL-3.0) and chess.js (BSD) — the full engine, every level, no limits.
Engine: Stockfish 19 via stockfish.js (GPL-3.0). Board: chessground (GPL-3.0; cburnett pieces GPLv2+). Rules: chess.js (BSD-2). This page's code is GPL-3.0 — see NOTICE.md. Vendored by scripts/build-chess.mjs.
Choosing a level
The eight levels combine Stockfish's own Skill Level setting, which makes it deliberately choose weaker moves, with a cap on how far ahead it searches. Roughly:
- 1–2 — for learning the moves. It leaves pieces hanging and misses simple captures.
- 3–4 — casual play. It punishes blunders but makes some of its own.
- 5–6 — a good club player. Expect to lose material if you leave a tactic on the board.
- 7–8 — very strong. Level 8 is full Stockfish with a short think; a draw against it is an achievement.
You can change the level mid-game; the next computer move uses the new setting.
Playing a game
Pick White, Black or Random and press New game. All the rules are enforced: castling, en passant, promotion (a picker offers queen, rook, bishop or knight), and every draw — stalemate, threefold repetition, the fifty-move rule and insufficient material. Undo takes back your last move and the computer's reply. The move list beside the board uses standard algebraic notation, so you can copy a game into any analysis tool afterwards.
If you close the tab mid-game, the position is kept in this browser and comes back next time you open the page.
How it works
Nothing is sent to a server. The engine is the single-threaded "lite" WebAssembly build of Stockfish 19 from the stockfish.js project, about 1.8 MB including its neural-network evaluation, and it runs in a background worker so the board stays responsive while it thinks. The board itself is chessground, the open-source board that lichess.org uses, and the rules come from chess.js. Because both Stockfish and chessground are GPL-licensed, the code of this page is released under the GPL too; it is served unminified at /apps/chess/.
Frequently asked questions
How strong is the computer at the highest level?
Level 8 is Stockfish 19 at full strength with about 1.5 seconds per move. The lite network is a little weaker than desktop Stockfish, but it still plays far above any human. Lower levels are deliberately weakened with Stockfish's Skill Level option and a shallow search.
Do I need an account?
No. There is no sign-up and nothing is uploaded; the engine runs in your browser. Your unfinished game is saved in this browser's local storage.
Can I play on my phone?
Yes. Tap a piece and then the square you want; the board resizes to the screen. The engine is single-threaded, so it works on any modern phone browser without special settings.
Can I play against a friend?
Not on this page yet — it is one player against the computer. You can choose either colour and switch sides between games.
More you can play in your browser
Related guides
- Chess puzzlesThousands of tactics from the Lichess database, matched to your rating.
- CheckersAmerican checkers against the computer, with forced captures and kings.
- BackgammonThe full race-and-hit game with gammons, against the computer.
- ReversiOutflank and flip discs on the 8×8 board against a three-level computer.
- All board gamesChess, checkers, backgammon, mahjong and more, all in the browser.
Want a game like this on your own site?
Chess isn't ours to give away — we host it, we didn't write it. But eleven of the games here we did write from scratch, and those are free for anyone to put on their own page: one line of HTML, no account, no permission, no attribution beyond a credit line.