Windmill Chess Analysis

ZappFlux

About this app

Windmill turns your own games into training. Import a game — or link your lichess or chess.com account — and get a report that names every mistake, shows the move you missed, and explains where the game actually turned. Then drill those exact positions until they stick.

Everything runs on your phone. Stockfish 18 is built in, there is no account to make, and nothing you analyse is uploaded anywhere.

GAME REPORTS
• Every move classified: brilliant, best, good, inaccuracy, mistake, blunder.
• An evaluation graph, accuracy for both sides, and accuracy by phase.
• Written in words, not just numbers: what the plan was, where it went, and what punished it.
• Choose your depth, from a ten-second look to a thirty-ply grind.

TRAINING BUILT FROM YOUR OWN GAMES
• Every mistake becomes a spaced-repetition drill that comes back until you get it right.
• Insights across your whole archive: which phase is your weak link, whether your errors come when you move fast, whether time trouble is where games are lost.
• Pick one thing to work on and track only that.
• Your openings, mined from the games you have actually played — including the lines that cost you points.

PUZZLES
• 8,700 puzzles bundled with the app. No connection needed, ever.
• Rated tactics, puzzle rush against the clock, opening trainer, endgame trainer judged by a tablebase, and a blindfold visualisation trainer.

PLAY
• A human-like bot at any strength from 400 to 2800, with a style: balanced, gambiteer or grinder.
• Play your ghost: a bot built from your own games. It opens with your repertoire, goes wrong as often as you do, in the phase you go wrong in, at your pace.
• Odds games, custom clocks, and a rating ladder against the bots.
• Play out the position you lost from, and find out whether you would have converted it.

SCOUT AN OPPONENT
• Type the username of the person you are about to play and read their public games: what they open with, which lines they score badly in, and what the clock says about them.

PRIVATE BY DESIGN
• No account, no sign-up, no ads, no analytics, no trackers.
• Your games, reports and training live on your device and are never uploaded.
• Works offline. Back up to a file whenever you like.

Free, and free of the usual bargain. Nothing here is paid for with your attention or your data.

Engine: Stockfish 18 (GPL). Pieces: cburnett (CC BY-SA). Openings and puzzles: the lichess open database (CC0). Windmill is not affiliated with lichess or Chess.com.

What’s new

Prep mode: get ready for a specific opponent.

• Scout someone and see the line your openings and theirs will most likely produce, and who runs out of book first
• Where a different move takes them into a line they score badly in
• Rehearse those lines, then play a ghost built from their own games
• Your own ghost now plays at your measured level, not at your chess.com rating