Chess AcuityFind the best move in any chess position.
An on-device chess analysis app for iPhone. The Stockfish engine is built in and runs entirely on your phone — your positions never leave the device.
- Offline
- Open Source
- Free
Four ways in
Get any position into the engine
However you start, Chess Acuity hands the position to Stockfish so you can find the best move and understand why.
Set up the board manually
Place pieces square by square to recreate any position, choose whose move it is, then analyze — no game required.
Set up from a photo
Point your camera at a board and Chess Acuity recognizes the position on-device. Nothing is uploaded — recognition runs entirely on your iPhone.
Import a game (PGN)
Paste a game in PGN notation, then step through it move by move and analyze any position along the way.
Play against Stockfish
Play a full game against the built-in engine at adjustable strength, then review the result and find the moves you missed.
Private & fully offline
Your positions never leave your phone
Analysis runs entirely on your device. Chess Acuity collects no data, has no accounts, no analytics, and no third-party SDKs — nothing is uploaded, shared, or sold.
- Works with no internet connection — the engine is bundled in the app.
- No accounts, no sign-in, no tracking. There is nothing to leak.
- On-device board recognition — even photos stay on your iPhone.
Open source & free
Free, with nothing to hide
Chess Acuity is free, has no ads, and its full source code is public under the GPLv3 — including the bundled Stockfish engine.
Free, no ads
No price, no subscriptions, no advertising, no in-app purchases.
Open source (GPLv3)
Read the code, audit the privacy claims, or build it yourself.
Stockfish inside
The acclaimed open-source engine, running natively on your iPhone.
Sharpen every move
Set up a position, hand it to Stockfish, and see the best move — offline, private, and free.
