♟️ CheckPause

A chess analysis tool that combines game-tree search with natural language generation to help players understand their own decision-making biases.

CheckPause evaluates every move with a local Stockfish engine, then lets any OpenAI-compatible model explain the engine data in plain language, alongside a clickable move list, a custom-drawn board, performance ratings, and a personal growth profile.

---

✨ Features

♟️ Review every move like a report card

• Stockfish scores every ply in the background, with a progress bar and a stop button; book moves are recognised from the bundled Polyglot opening book and skip the engine entirely.
• Every move gets a label the way a review report does it — Brilliant, Great, Best, Excellent, Good, Book, Forced, Only move, Inaccuracy, Mistake, Miss, Blunder — and the game an accuracy rating on a five-tier scale (Optimal / Precise / Competent / Steady / Volatile).
• Click any move to jump to that position; the board draws the engine's best-move arrows, shows a live evaluation bar, and flips with one click.

💬 Ask the engine data in plain language

• The engine data (PGN plus per-move scores and best moves) is passed to the model as context, and answers stream in token by token.
• Follow-up questions work like a coach conversation: "Wasn't 10.Nxb5 just losing a knight?" gets an answer grounded in the numbers on screen.
• Works with DeepSeek, OpenAI, OpenRouter, or a local model — anything that speaks the OpenAI API.

🎮 Play the computer

• A 100–3000 rating slider; 1320 and above is calibrated by Stockfish's own Elo limiter, and below that Skill Level and a node budget approximate it.
• Common time controls (1+0 through 30+0, with increments or unlimited), White or Black, and selectable openings and endgames.
• Click-to-move, promotion picking, undo, resign — and a one-click send to analysis when the game ends. The setup pickers lock once a game is under way and unlock on New game.

🧩 Train with puzzles

• A curated Lichess sample ships with the app, and you can import your own open collections (Lichess CSV, or FEN-based PGN); large collections are read lazily.
• Correct/wrong feedback with automatic opponent replies, hint arrows and retry; rating and themes shown per puzzle.
• A Favorites collection automatically gathers the puzzles you star or miss.

📈 Watch your numbers

• Total games, average accuracy, and the latest game's accuracy at a glance.
• A per-game history table with the date, the rating tier, and the percentage.

🎨 Make it yours

• 10 Lichess open-source piece sets, 6 board themes, and light/dark modes, applied instantly and saved.
• Move sounds for quiet moves, captures, checks, castling and promotions, in a Default set or Off; every clip is synthesised by the project, with no third-party assets.
• A Chinese or English interface, switchable at any time; analysis depth (12–18) and evaluation depth (10–22) adjustable under Personalization.

🔒 Private by design

• Your games and API keys stay on your machine; analysis never depends on the cloud.

---

🚀 Quick Start

Requirements: Windows 10/11 (x64) or macOS 11+ (Apple Silicon or Intel). No Python needed — Stockfish, the opening book and all assets are bundled.

Windows users

1. Get CheckPause_Setup_2.0.2.zip from the Download section at the end of this file, then extract it to get CheckPause_Setup_2.0.2.exe.
2. Run the installer and follow the prompts — no administrator rights needed, and a desktop shortcut is optional.
3. Launch CheckPause from the desktop or Start Menu; the first launch lets you sign in to a cloud account, create one, or continue offline.
4. Open Settings → API settings... and fill in the API key, base URL and model name for an OpenAI-compatible endpoint (for example DeepSeek).
5. Paste or open a PGN on the Import tab, click Analyze, then ask questions on the Analysis tab.

Analysis and board features work without an API key; only AI chat needs one.

macOS users

1. Download the .dmg for your chip from the Releases page (M-series for Apple Silicon, Intel for Intel Macs).
2. Open the .dmg and drag CheckPause into Applications.
3. The build is unsigned and not notarized. On first launch, right-click the icon → Open, or allow it under System Settings → Privacy & Security → Open Anyway.
4. From there the steps match Windows (set an API key, import a PGN, start analysis).

---

⚙️ Configuration and data

• Settings → API settings... is the bring-your-own-key path: enter the API key, base URL and model name for any OpenAI-compatible service. Signing in to a cloud account switches the app to the hosted tier instead.
• User data lives in %APPDATA%\CheckPause\ on Windows and ~/Library/Application Support/CheckPause/ on macOS: profile.json (username, language, theme, appearance, history) and settings.json (API config); legacy profiles migrate automatically.

---

❓ FAQ

• Do I need an account? No. The board, engine analysis, play and puzzles all work in offline mode; a cloud account only unlocks the hosted AI tier.
• Do I need an API key? Only for AI chat. Enter your own key under Settings → API settings..., or sign in to use the hosted tier.
• Is my game uploaded? Local engine analysis never leaves your machine. When you ask the AI questions, the game and engine data are sent to the model you configured — the same is true on the hosted tier.
• Why does Windows SmartScreen / macOS warn? The builds are unsigned: choose More info → Run anyway on Windows, or right-click the icon → Open on macOS.

---

🙏 Credits

• Pieces come from Lichess open-source piece sets (cburnett, merida, chessnut, fantasy, spatial, celtic, kiwen-suwi, rhosgfx, totoy, mpchess), each owned by its author under GPLv2+ / Apache-2.0 / MIT / CC BY / CC0 licenses.
• Engine: Stockfish (GPLv3); the opening book is compiled from public opening lines.
• The installer is built with Inno Setup and uses its official Simplified Chinese language file (installer/languages/ChineseSimplified.isl, maintained by Zhenghan Yang).
• License: CheckPause is proprietary software — Copyright (C) 2026 CometZZZ, all rights reserved. See LICENSE. Bundled components keep their own terms: Stockfish is GPLv3 (source available at https://stockfishchess.org/download/), and the piece sets keep the licenses listed above.

---

⬇️ Download

Latest: CheckPause v2.0.2 (Windows x64)

• 🚀 Fast mirror (recommended in China): CheckPause_Setup_2.0.2.zip — the same file served from a host that is reachable without the usual throttling, usually done in well under a minute
• 📦 Download from GitHub (136.3 MB — ships with Stockfish, the opening book, piece assets, move sounds, and a curated Lichess puzzle set)
• SHA-256: A47534238A2E6A98D581B3C93B0659B6BF50E6F024F3A48B31C5A1D280E6E0DD (the zip; both links serve the identical file)
• Extract the zip to get CheckPause_Setup_2.0.2.exe (SHA-256 C89C713F9F6D6C977672E7D0717E69E628FA86A8DF3D4FD0E01985A9D5DEAB34), then run the installer and launch CheckPause from the desktop or Start Menu. The build is unsigned; if SmartScreen appears, choose More info → Run anyway.

Latest: CheckPause v2.0.2 (macOS)

• 🚀 Fast mirror (recommended in China): M-series (168.3 MB) · Intel (97.1 MB)
• 📦 Download from GitHub (both .dmg files on the release page)
• SHA-256: arm64 AF2B690EB0C320BD7422EB68A757862AA435D6B0BB89670BDE75C2CD5FDBF1F1, Intel D6AC6EB0FC2BC39B82DC73C2B6782A9556E5E8EB611001D978398C438BA0AADC
• Open the .dmg, drag CheckPause into Applications, then right-click the icon → Open the first time (the build is unsigned and not notarized).
• All releases: https://github.com/Comet-zzz/CheckPause/releases

---

Chinese README