Six tools for your opening repertoire.
One single flow.

Your repertoire is a branching structure — variations, sub-variations, alternative lines — not a list of PGN files. ChessNotes gives you a real tree on a zoomable canvas, with an automatic layout that redraws itself every time you add a move. No text files, no manual versioning, no dragging nodes around.

You build it by playing. Double-click a node and the board opens on that exact position; make a move and a new branch is born in the right spot. Play a move that already exists somewhere and the lines merge — transpositions become a single node, so you map a position once and it counts everywhere it occurs. Big trees stay readable: the View menu folds the tree to an overview or focuses on a single line.

Every move carries a note. Select a node and write the idea in the sidebar — a plan, a trap, a coach-style reminder — and it is shown back to you when you train that position. Changes autosave and sync across browser, tablet and mobile, and you can export PGN any time.

Stockfish 19 with NNUE runs right on the page you're looking at: the full build, with the big neural network, on computers; a lighter build on phones and tablets, so it loads fast and stays stable there. No remote servers, no install, no plugins: it's compiled to WebAssembly and loaded lazily the first time you use it. The main thread stays free, the engine thinks on a dedicated Web Worker, values stream in while you think about your move.

Before waking the local engine, ChessNotes queries Lichess cloud eval: for common positions (openings, known theory) the deep, already-computed evaluation comes back near-instantly. Only when the position is truly new does the local engine kick in, with a synced eval bar and depth growing visibly on screen.

The integration is quiet. Open the board and expand "More tools": the engine, a move database (what masters and the Lichess community play) and your own chess.com games sit together, out of the way until you need them. The eval bar appears next to the board and the best lines update in real time. All without leaving the study flow, without opening a second tool.

Most players already have a repertoire: it is in their games, not in a file. Connect your Chess.com or Lichess username (public games only, no password) and ChessNotes reads your games in the background, groups them by colour and opening — "Caro-Kann Defense (Black)", "White vs Sicilian" — and lists every opening you play often enough, with games and score. Tick the ones you want and each becomes a tree of the moves you really play against the replies you really meet.

When you play several named variations of the same opening, each gets its own repertoire, grouped under that opening, so you train each line once. The tree goes deeper where you have many games and stops where you have few, so it stays readable. Later, Update adds the new branches from your latest games to the repertoire you already have, without deleting anything.

Then the engine looks at your habits. For each repertoire, ChessNotes shows where your games leave the tree, which opponent moves you have not prepared yet, and which of your habitual moves Stockfish says cost you. "Mistakes in your openings" (in the account menu) goes through the opening moves of your recent games and groups the mistakes you repeat. One click puts the better move in your tree and at the front of your next review.