Play your way
Start a game as White or Black, or let Ironwood choose a side at random. When you play Black, Stockfish makes the first move and the board follows your perspective. Adjust the engine’s strength and choose among five piece sets: System, Cburnett, Merida, Royal Rascals, and Undead Court. Optional move animation and sounds make moves, captures, and checks easier to follow.
Analyze the whole game
Run Stockfish 19 with its full NNUE network directly in your browser. Review evaluations, best moves, principal variations, move quality, accuracy, and the turning point of a game. Pause and resume full-game analysis, step through critical positions, and export annotated PGN, analysis JSON, or a printable report. Choose letter or figurine notation for the move list.
Build your library
Saved Games keeps games against Stockfish and imported games together on this device. Import a single PGN or choose games from a multi-game PGN collection; search by player, select the games you want, and skip duplicates. Filter the library by player or analysis state, mark favorites, and reopen a game with its saved analysis.
Keep control of your data
Ironwood saves games and display preferences locally. Download a versioned JSON backup, then restore it by merging with your library or replacing existing games. Storage Information shows game counts and browser usage. Install the app and explicitly store the engine for offline play; your games and analysis stay available without an account.