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| 🧠 Explain | The engine doesn't just score the move: arrows on the board show the material that falls and the reply that makes the difference. |
| 📚 A real database | PGN, lichess.org, chess.com and ChessBase files; search by position on millions of games, in seconds. |
| 🎯 Train with a tutor | Play the engine from your own opening book; a tutor stops you on mistakes and offers to take back or explain. |
| 🌐 Play online | lichess.org and freechess.org from the same board — engine off, clocks on, and an estimated Elo for both sides when the game ends. |
| 🔁 Everywhere | Native on Windows, macOS and Linux, with an Android companion; sync your folder over FTP, WebDAV or Git. |
TL;DR
An open source chess database for studying, training and playing: light,
simple, with what really matters. For Windows, macOS and Linux.
Web site: https://yafb.net/pragma-chess/ (English, Italian and Spanish, with
screenshots, downloads and the guide) ·
Discussions
for questions and ideas · Issues
for problems. Contributing: report a wrong
explanation, translate, write code. See DESIGN.md for the vision and
architecture, CHANGELOG.md for what changed, and
DISTRIBUTING.md for how we make it known.
Download
The latest version, always at these links:
Every version, with files named after it, is on the
releases page.
The packages are built by GitHub Actions from packaging/.
Try the Android app
The mobile app is in beta and we'd love your feedback; it will soon be on
the official app store. It reads your
databases offline, records the games you play on the phone and analyses them
with an engine app such as Stockfish (any Open Exchange engine, as in
DroidFish; the app offers to install one); pair it with the desktop client in
Options ▸ Connect Mobile App… to keep both in sync.
Download the APK
(Android 8+, about 14 MB; it has the same version as the desktop client). Open the link on
the phone and allow installing from that source when Android asks. Tell us
what works and what doesn't in the
issues: the phone
model and the Android version help.
Desktop client (Qt 6 Widgets)
The GUI lives in gui/qt. It talks to the database through the GameDatabase
interface (gui/qt/src/app/GameDatabase.h).
Databases are .pdb files — SQLite databases tagged with PRAGMA application_id
(PRAG) and a schema version in PRAGMA user_version, upgraded by migrations
when an older file is opened. By default they live in
a localized chess folder in the home directory, next to Desktop and Documents:
~/Chess/Pragma/Databases/ (English)
~/Scacchi/Pragma/Databases/ (Italian)
Projects are .pch files (YAML) saved from the File menu. A project is the
workspace: it captures the whole working environment — database, open game and
move, board orientation, engine, which panels are visible and how much room
each one takes — and is stored by default in ~/Chess/Pragma/Projects/
(localized like the databases folder). The last session is restored
automatically on startup, attached to its project file. The View menu shows
and hides the panels, and View ▸ Reset Panel Layout puts them back.
An existing chess folder is reused if the language changes; PRAGMA_CHESS_DIR
overrides it. On first launch the folder is seeded with Classic Games.pdb.
Entering and explaining games
Game ▸ New Game starts a game that is entered move by move on the board
(click or drag the pieces) and analyzed as it grows; Game ▸ Save Game to
Database adds it to the open .pdb. Playing a different move in a stored
game never changes it: the new line becomes an unsaved game.
Explain (the light bulb between the previous and next move buttons, or
E) shows why the evaluation is what it is compared with the position
before the last move: the refutation of a mistake, the material a move wins,
a mate it allows or misses. It starts the engine if needed: the border of the
board breathes while the engine is looking and turns blue when the answer is
on the board.
This is the beginning of the README. Read the rest at the original. Read the full README ↗
