Practice Against a Bot That Matches Your Level

The ChessOnyx bot runs on real Stockfish — the same engine that powers the game analysis — throttled to any strength between 400 and 3200 Elo. Move the slider from beginner to grandmaster level and the bot plays plausibly at that rating, instead of alternating between perfect moves and obvious blunders.

You choose the engine build (from the lightweight Stockfish 10 to Stockfish 18 with its full neural network), pick your color, and can optionally force a specific opening: search over 15,000 named variations and the bot will follow that line — an ideal sparring partner for opening practice.

Games are played right on the analysis board, entirely in your browser — the engine calculates locally, nothing to install. After the game, Stockfish is one click away from showing your accuracy, mistakes and missed chances.