Every loss has a moment it turned. Train that moment.
ChessMend imports your own games, finds the exact moves that cost you the game with Stockfish, and turns them into a personal, spaced-repetition puzzle set — built from your mistakes, not a stranger's. Then keeps going into your openings: a repertoire coach that drills your prep and hands you off to the engine the moment you step outside it.
Import a game, watch the blunder become a puzzle.
One short loop: pull a game, let Stockfish score it, and drill the exact move that cost you.
You already know roughly where you're losing rating. You just don't drill it.
Generic puzzle apps train tactics that have nothing to do with your games. The blunder that actually cost you last Tuesday's rapid game never comes back around — and the opening you keep reaching for stays a blind spot because nothing ever points at it specifically.
Import → analyze → practice → refine
Import. Pull games straight from your chess.com or lichess.org account, or a single game by link.
Analyze. Every move is run through Stockfish and scored Best through Blunder, for both sides, by opening/middlegame/endgame.
Practice. Mistakes above your threshold become puzzles, scheduled with a Leitner spaced-repetition box so misses come back sooner.
Refine. Opening Stats shows exactly which openings are winning or losing you games; Opening Coach drills the ones that need it.
A full training loop, not just a puzzle screen.
Four areas that work together — each with its own deep dive.
Opening Coach & Stats
See which openings are winning or losing you games, then drill a repertoire against a coach that hands off to Stockfish the moment you step outside the book.
Import & Game Review
Unlimited Stockfish analysis of every imported game, move-quality tiers by phase, and coaching notes on where your rating is actually leaking.
Puzzles & Spaced Repetition
Puzzles built from your own blunders, a Daily Puzzle Challenge, single-attempt exams, and "No Mistakes" survival drills.
Bots & Opening Traps
An adjustable engine opponent from ~300 to ~2800 Elo, custom material handicaps, and twenty scripted trap-heavy openings.
See it before you install it.
A few highlights — every feature page has its own full gallery, and every shot below opens full size.
"Your middlegame accuracy is fine. It's the endgame conversions that are costing you rating — three of your last five losses were winning positions you let slip after move 40."
- Opening3.1% blunder rate
- Middlegame4.4% blunder rate
- Endgame7.8% blunder rate
- Estimated skill bandStrong Club
Your openings, scored — then drilled until they stick.
Stop drilling someone else's tactics.
One installer. Stockfish and piece artwork bundled in — nothing else to set up.
Questions, bugs, or a coaching/club license?
Send a message and it goes straight to our inbox — we read every one and usually reply within a day or two.
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