Play this position against the computer
White starts from setup 229, Black from setup 162 — the balanced pair shown on the home page. The computer runs in your browser.
How strong is it, honestly
Two opponents answer here, and the page always says which one. The real one is Stockfish 19 Lite compiled to WebAssembly — the same engine that analyses games at the top level, running in your browser. You choose its strength next to the board, from about 800 to 2000, so that a beginner gets a game rather than a demolition.
Stockfish is 1.2 MB over the wire, so it loads only when you start a game — not for everyone who opens the page. Until it is ready, a small engine built into the site answers: it is far weaker, but it replies instantly. The rules are the same for both and are not theirs: moves, Chess960 castling, check and the end of the game come from the rules library that drives the board here and the Android app.
Everything is computed in your browser. No position and no move leaves this page.
Stockfish is free software under the GPLv3; its source is at github.com/official-stockfish/Stockfish, the WebAssembly build at github.com/nmrugg/stockfish.js. CH960 is GPLv3 as well.
Where to go next
This pair in the encyclopedia · About this setup · Encyclopedia of balanced pairs
For a real opponent — people or a full engine with mentors — there is the Android app.Im Browser oder in der Android-App. Nichts zu installieren · Kostenlos, ohne Werbung