Opening Lab — Chess Opening Repertoire Trainer

Create and refine a chess opening repertoire quickly. Import courses, studies or pick from the Opening Lab library; train either side, practise with Opening Sparring, review online games, and prepare for opponents.

Build

Build & Refine Your Chess Repertoire

Import a repertoire PGN, build one yourself, or generate an editable snapshot of any online player's recurring opening habits. Change or add lines using master and online games, evaluation data, or Opening Lab suggestions.

Analyze

Repertoire Analysis & Opponent Prep

Run a customizable repertoire review to uncover dangerous opponent ideas, or prepare for an online player by finding repeated opening weaknesses in their games. Review actionable findings on a board and export reports or move trees as PDF.

Review

Review Your Online Games

Cross-check your opening moves played in online games to see whether you remember your lines and use deviations to improve. Get a detailed report on mistakes or directly train the relevant positions.

Train

Flexible Repertoire Training

Train your complete repertoire or selected parts with spaced repetition, or choose any opening or line in your repertoire and train everything from that position.

Practice

Opening Sparring

Practise real opening decisions from either side against frequency-weighted moves from online or master game databases. Every legal move is evaluated so you can see where your choices gain or lose ground.

Switch Sides

Opponent Moves

Switch sides to ensure you have a strong command over what opponent moves are covered in your repertoire for a given position so you don't start guessing over the board.

Everything in Opening Lab

Complete feature list

From your first repertoire to targeted practice, game review, and opponent preparation.

Build a repertoire that suits you

Pick a repertoire from the library: 40 ready-made repertoires: full White and Black coverage, focused opening studies, and aggressive choices — all editable.
Import PGNs: Bring in your own files and annotated courses, with chapter selection and connected custom starting positions where supported. Clear illustrative and reference material is kept out of the trainable repertoire.
Import Lichess Studies: Choose usable chapters instead of importing everything, and retain their useful comments.
Build from online games: Create an editable repertoire from a Lichess or Chess.com player's actual opening choices — including your own.
Create from scratch: Build a broad repertoire or a specific line by playing legal moves on the board.

Explore, edit, and understand

Interactive move tree: Browse branches, see the current path, and start training or editing from a chosen position.
Flexible repertoire editor: Add alternatives for either side, replace or delete a move across matching positions, and undo or redo draft changes before saving.
Practical move suggestions: Extend coverage with opponent replies selected for your breadth and depth settings.
Move Explorer and analysis: Compare move popularity, game results, and available evaluations using online or master-game data. Filter online data by rating and time control, inspect master games, or open a position for analysis.
Notes, critical positions, and line tags: Keep explanations, flag positions worth revisiting, and organize complete lines with tags. Position-based additions also apply to transpositions.

Train the way you learn best

Daily Training: Use spaced repetition across the repertoires you include in your daily plan, with progress tracking and focused retries after mistakes.
Customized Training: Practise Random Lines, Random Positions, Specific Lines, Critical Positions, or Difficult Moves.
Own moves or opponent moves: Learn your responses, or switch sides to recall the opponent alternatives covered by your repertoire.
Control depth and entry: Set training depth, start from a chosen position, and use Target Moves Only, First New Move, or Always Start At Move 1.
Guidance when you need it: Introduce new moves with optional first-time arrows; Reveal shows the answer and available notes alongside the board. Choose manual advance or automatic continuation and adjust autoplay speed.

Test yourself against realistic opening choices

Opening Sparring: Practise against common human moves from online games for a selected rating range, or use master-game data — rather than only an engine's best replies.
Play your repertoire, or against it: Practise your side against replies beyond your repertoire, or switch sides and face its saved continuations. You can also spar without a repertoire or from a selected position.
Feedback and decision review: Every legal move is accepted. See available engine-based move-quality feedback separately from repertoire coverage, then revisit deviations and mistakes from the completion summary.

Find gaps and learn from real games

Repertoire Analysis: Find weak own moves and important missing continuations, so you can improve what you actually need to play.
Critical Positions and Difficult Moves reports: Review key positions and moves that repeatedly cause trouble in unguided training, then turn them into focused practice.
Game Reviews: Connect your Lichess or Chess.com games to review opening deviations and train the resulting errors.
Opponent Preparation: Use public Lichess or Chess.com games, or an uploaded PGN game database, to find an opponent's weaknesses or how they respond to your repertoire, focusing on relevant deviations. Refine the date range, inspect the games, and save preparation reports.

Import, export, print, and keep your work

Flexible multi-dialect PGN support: Import variations, symbolic annotations, comments, and supported custom positions from different PGN sources. Move legality and chapter checks help identify material that cannot be used.
Two PGN export choices: Use Opening Lab PGN to preserve app-specific annotation context for reimport, or Clean PGN for readable moves and comments in other chess tools.
Printable PDFs: Print your repertoire tree, Critical Positions, Difficult Moves, Repertoire Analysis, Game Reviews, or Opponent Preparation reports for offline study.
Synchronized work: Keep repertoires and training progress with your account across devices. Export your account data, and use the in-app Help for detailed guidance.