Every feature, one page.

After any game — vs the engine, vs another player, or one you uploaded — write what you were thinking. Plans, threats you saw, lines you calculated. Not "good move," the actual reasoning. Your games live on your profile.

Go to my games

Each annotation is graded on whether the thinking is concrete and sound — calculation, plans, evaluation — vs. hand-wavy. Your strongest and weakest moments become visible.

See top-scored annotations

Blunders from your own games are tagged by motif and pawn structure, then turned into puzzles. You drill the exact patterns you personally get wrong.

Open Weak Spots

A short spaced-repetition session mixes due puzzles with fresh ones, biased toward your current weak spots. The queue updates as you play more games.

Start today’s session

From /play you can spar against an adjustable Stockfish, or queue up for a rated PvP match against another ChessDecoded member over real-time WebSockets. Both feed straight into post-game annotation.

Start a game

Already have games from Lichess, Chess.com, or OTB? Paste the PGN and the same annotation + analysis flow runs on those positions too.

Import a game

On any position, get a multi-paragraph engine-grounded explanation — concrete lines, key squares, plans for both sides. Not generic prose, anchored to the actual evaluation.

Try on a position

Build move-tree repertoires with reasoning, notes, and your own Q&A attached to each node. Includes a quiz mode that tests whether you actually remember your prep.

Open repertoires

On any analyzed position, see how the same opening — and same pawn-structure family — has been played and annotated elsewhere. A retrieval layer over the community library.

Browse via a position

When you miss a puzzle, the coach explains specifically why your move failed and why the right one works — tied to the move you actually chose.

Solve puzzles

Read how other members reasoned through positions — grouped by opening so you can study the way stronger players think about lines you actually play.

Open Explore

Ask a question about any position; other members answer. Questions are scoped per position, so you see prior discussion on the same spot before you write your own.

Browse questions

Bookmark any deep-analysis position you want to come back to. They’re collected on one page so reviewing prep doesn’t mean retracing your steps.

View saved analyses