Chess Trainer Help

Start here

Chess Trainer revolves around one board. Move between Play, Navigate, Analyze and Train without losing your place. On larger screens Navigate and Analyze share the workspace beside the board.

Play: start a human or engine game.
Navigate: move between sources, saved positions and repertoire positions.
Analyze: inspect numerical evidence, continuations and readable chess explanations.
Train: review positions prepared from your opening repertoires.

The app adapts to the actual browser width and height. On small windows it may move controls or information around the board so the complete board remains usable rather than cropped.

Board & navigation

Playing and selecting moves

Click or tap a piece, then its destination. Legal destinations are highlighted. Position setup and move-explanation tools can temporarily use the board for placement or move selection instead.

◀ / ▶: Go to the previous or next recorded position.
☆: Save or unsave the current position as a favorite.
Moves between arrows: Shows the recent path to the current position. On small screens, tap the leading … when present to open the complete move list.
Flip board: Open the hamburger menu and choose Flip board.

On wider layouts, drag the vertical separators to give more room to the board, Navigate or Analyze. The board-pane preference is shared across board-centered workspaces so switching modes does not make the board jump to a different size.

Play chess games

Open Play, configure White and Black, and choose Human or an installed engine for each side. Engine players can use their own search depth.

Chess clock

Minutes per player > 0: a normal countdown clock.
Minutes per player = 0: unlimited game; each player's clock counts thinking time upward.
Increment: seconds added after each completed move in a timed game.

Start begins the configured game. Active games can be paused and resumed. Restart discards the current score after confirmation and begins again with the same player configuration.

The game score is read-only. Use the board arrows to inspect earlier positions. On larger screens, long move lists scroll inside the Game moves area so the chessboard stays visible.

Navigate chess openings and positions

Navigate moves through the current chess position, Lichess Opening Explorer sources, saved positions and repertoire trees.

Sources: Switch between Setup, Repertoire and Saved positions without leaving the shared board.
Lich: Use available Lichess Opening Explorer information. Cloud Eval and Opening Explorer are separate services.
Arrows: Move through the available positions in the selected source.
Games / score: Shows matching Lichess games for the active speed and rating filters when available.

Use the shared board arrows and source tabs to reach the position you want. Switch to Analyze when you want numerical evidence, continuations or an explanation of that position.

Navigate and Analyze table columns

Column	Meaning
Move	The candidate continuation from the current position.
Freq	How often the move was played from this position in the selected Lichess population.
Lich	Lichess result score, using wins plus half of draws.
Score	Move-comparison score shown in this table. Repertoire selection uses rating-corrected practical SCORE and checks engine safety separately.
Tree	Practical score within the currently retained repertoire tree.
Eng	Engine-derived expected score/evaluation for the move.
Rtg	Average rating of players who chose the move.
…	Additional move details such as PV, opening and exact source information.

A dash means the metric is not currently available for that move; it does not necessarily mean the move is bad.

Build chess opening repertoires

Go to the position you want as the repertoire root, open Train → Repertoires → Start repertoire here, choose a side and a name, and create it. The current Lichess filters supply the repertoire's empirical move data.

Only positions where it is your repertoire side's turn become learnable cards. Opponent/support positions are retained so the route through the opening tree remains meaningful. Your-move Score is rating-corrected practical Lichess performance; engine evaluation is a separate safety check. By default, 20 games are needed to consider a move and 100 for automatic selection. Opponent replies with observed games enter a global preparation frontier ordered by how much root coverage they add; preparation has no fixed coverage target or branch cap. See the repertoire foundation for full rules.

Suspend: keep the repertoire but exclude it from active training and preparation.
Delete: remove the repertoire itself while leaving reusable shared position knowledge available to other trees.

Analyze a chess position or move

Open Analyze to review numerical evidence, continuations and a readable explanation of the current position. The explanation uses available engine and empirical evidence to summarize practical ideas, strengths, risks and candidate moves.

To explain a specific move, use the Move tab, choose the move on the board when prompted, then request the explanation. Analyze settings use Save and Cancel semantics and, on large screens, replace the Analyze pane without covering the board.

Train prepared opening positions

Training uses prepared learnable positions from active repertoire trees. It reads the same authoritative repertoire data that Navigate uses rather than simply training whichever position happens to be visible on the board.

Start training from the available course. The learning-progress window summarizes recorded, learned, due and suspended material together with review and correctness information.

If nothing is due, that is not an error. Continue preparing repertoires or return when scheduled reviews become due.

Set up a chess position

Use the Setup tab on Navigate to edit the shared board position. Return to Play and choose Start → Current position when you are ready to play it.

You can reach a position by playing legal moves, or place pieces directly. The legal-move path updates turn, castling, en-passant and move counters automatically. Direct placement lets you choose pieces, squares and the side to move explicitly.

Expand More position options when you need castling rights or other FEN-level details. Apply commits the edited position as the current board position.

Stockfish, Lichess Cloud Eval and Opening Explorer

Local Stockfish

Stockfish runs in the browser using the engine files supplied with Chess Trainer. Engine settings choose the engine, search depth and candidate-line count.

Lichess Cloud Eval

Cloud Eval supplies previously calculated engine evaluations when available. It is separate from Opening Explorer.

Lichess Opening Explorer

Opening Explorer supplies game-frequency, result and rating statistics. Speed and rating filters change the game population and therefore can change move frequencies and results.

If a suitable cloud evaluation is unavailable, local browser evaluation can be used. Repertoire engine safety uses the shared engine, target depth and 1-PV profile under Train → Settings; the profile is shared, not copied into each new repertoire.

Saved positions and comments

Press the star in the board navigation strip to save or unsave the current position. Open Navigate → Saved to browse saved positions.

Use the comment control in Analyze to attach your own note to the current position. The comment follows the position rather than one particular screen.

Chess Trainer settings

Open the hamburger menu and choose Settings. User settings include Lichess speed/rating filters, analysis arrows, board design, piece design, move notation and chess sounds.

General engine/search maintenance is under Admin → Engine settings. Shared repertoire-preparation engine and depth are configured under Train → Settings, with 1 PV.

Hamburger-menu tools

Flip board: Reverse the board orientation.
Settings: Open appearance, notation, analysis-display and Lichess population filters.
Help: Open the in-app guide.
Annotate screen: Freeze the visible Chess Trainer surface, draw on it, then copy, save or use it in a report.
Send feedback: Report a problem, request a feature, or suggest an improvement, with optional screenshot and technical context.
Admin: Owner-only maintenance hub for layout preview, engine settings, evaluation queue, reload, backup, key management, analytics and feedback.

Install Chess Trainer as a web app

Chess Trainer includes a web-app manifest and service worker. In a supporting browser, use Install app or Add to Home screen. An installed PWA can open in its own app-like window without normal browser chrome.

The application shell and static assets are cached for resilience, but server-backed features still need the server and Lichess statistics require network access.

Troubleshooting

Stockfish analysis does not start

Wait for engine loading to finish, confirm an installed engine is selected, then try Eval again. If needed, open Engine settings and verify the engine and depth values.

Lichess opening statistics are empty

The position may have no matching games for the chosen speed/rating filters, Opening Explorer access may not yet be configured on the server, or the network may be unavailable. Cloud Eval and Opening Explorer are separate, so one may work while the other does not.

Training says nothing is available

Make sure you have an active repertoire with prepared learnable positions. A suspended repertoire is not part of active training.

The board looks too small or a pane is cramped

Resize the browser or drag the workspace divider on larger screens. On small or short windows the app automatically changes composition to keep the complete board visible.

I cannot find a control that used to be visible

Setup is beneath the board, comments are in Analyze, and repertoire management is in Train. Navigate owns position sources; Analyze owns numerical and continuation analysis.

I found a layout or behavior bug

Use ☰ → Send feedback. Choose whether to include the current app view and technical context; you can annotate the screenshot before sending it.

Chess Trainer glossary

FEN: A compact text description of one chess position.
PV: Principal variation: the engine's representative best line from a position.
Depth: Engine search depth. Higher values usually mean more calculation and more time.
Cloud Eval: Previously calculated Lichess engine evaluations retrieved from the network.
Opening Explorer: Lichess database statistics about moves played by real players.
Position Knowledge: Reusable information stored for a chess position, independent of a particular repertoire.
Repertoire: A prepared opening tree from a chosen root and side.
Learnable position: A repertoire position where it is your side to move and which can become a training card.
Prepared frontier: The upcoming learnable part of a repertoire for which enough information has been prepared.
UCI move: Coordinate move notation such as e2e4, commonly used internally by chess engines.

Help for playing, exploring, analyzing and training chess openings.