Stockfish AI Chess

Ten engines. Your rules. Turn your iPhone or iPad into a chess engine battle arena. Challenge powerful chess engines yourself, pit them against each other in head-to-head dogfights, or run your own tournaments. Who handles a fast time control best? Who finds the winning idea in your favorite position? Set the conditions and watch the battle unfold. MEET YOUR TEN CONTENDERS Stockfish 19, Reckless 0.9.0, PlentyChess 8.0.0, Pawnocchio 2.0.1, Obsidian 16.0, Cinder 0.6.1, Viridithas 20.0.0, Halogen 16.0.0, Clover 9.1, and Starzix 6.1. All ten run locally on your device, ready for offline play, analysis, matches, and tournaments. STAGE ENGINE DOGFIGHTS Pick the rivals, choose their colors, and set Time per move or Time per game. Let two different engines face off, or match an engine against itself. Watch their plans develop, pause and resume the action, then save or export the game to study the decisive moments. RUN YOUR OWN ENGINE TOURNAMENTS Choose two to ten engines for an all-play-all showdown, with 1–10 games per pairing. Set the clock, follow the standings, and see the winner or joint winners, points, wins, draws, and losses. Repeat with different time controls and discover which engine comes out on top in your own tournaments. Colors alternate across repeat games, and single-game pairings use balanced colors. PLAY, EXPERIMENT, IMPROVE Play as White or Black against your chosen engine. Stockfish offers 19 difficulty presets, from beginner settings to World Champion at full strength. Other engines play at full strength. Choose a fixed thinking time or a game clock, or control both sides to explore your own ideas. SEE THE IDEAS BEHIND THE MOVES Analyze games and positions with evaluations, suggested moves, search depth, speed, and position counts. Follow up to three analysis lines and board arrows with engines that support multiple lines. Choose timed analysis or Forever, and view win/draw/loss percentages when supported by the engine or opening data. EXPLORE OPENINGS AND ENDGAMES Discover familiar lines and fresh ideas in an offline opening book with over 290,000 filtered positions. Adjust Opening Book Variety for more consistent or varied play. Complete 3- and 4-piece Syzygy tablebases are included and used automatically by Stockfish 19. Download the optional complete 5-piece WDL + DTZ set, about 980 MB, for more exact endgame coverage. Both kings count toward the piece total; downloaded tablebases work offline too. TEST YOUR DEVICE'S CHESS SPEED Run the 15-second Stockfish 19 benchmark and watch the Relative Speed bar progress. See positions per second and your device's Relative Speed result. Repeat the test to compare your device's search performance. SAVE, SHARE, MAKE IT YOURS Save games, import and export PGN, copy positions as FEN, and revisit earlier moves. Import public games from Chess.com or Lichess with an internet connection. Choose boards and piece designs, customize coordinates and move highlights, and enable optional move sounds and haptics. Sound and haptics are off by default. Adjust CPU / Threads Usage and hash memory within your device's supported limits. Play, analysis, matches, tournaments, benchmarks, and the opening book work offline. Public-game imports and optional tablebase downloads require internet access. Engine results vary with hardware, time control, and settings. Difficulty ratings are approximate presets. Bundled engines are updated through app updates. Independently developed by Tughan Y. Karsli. Not an official app of the Stockfish project, other engine authors, Chess.com, or Lichess.