Xadreco

Chess engine by Dr. Beco, since 1988.

Copyright (C) 1988-2026 by Ruben Carlo Benante rcb@beco.cc

Version	9.0
Protocol	UCI (Universal Chess Interface)
Platforms	Linux, Windows (cross-compiled)
License	GPL v2
Play online	lichess.org/@/Xadreco
Source	github.com/drbeco/xadreco

Features

• UCI protocol (native, no wrapper)
• Opening book (livro.txt)
• Iterative deepening with alpha-beta pruning
• Fail-soft alpha-beta
• Non-blocking search with pthreads input
• Arena-based memory management
• Single-file C source (~3,800 lines)

Build

Linux:

make xadreco

Windows (cross-compile from Linux):

make xadreco.exe

Requires: gcc (Linux), mingw-w64 (Windows cross-compile).

Usage

Xadreco speaks UCI. Connect it to any UCI-compatible GUI:

• Arena (Windows): Engine > Install New Engine > select xadreco.exe
• lichess-bot: set protocol: "uci" and executable: "xadreco -b livro.txt" in config.yml
• Command line: ./xadreco -b livro.txt -v

Options

Flag	Description
-b <file>	Opening book file
-v	Verbose (debug output to stderr)
-vv	Extra verbose (board display)
-r <seed>	Random mode
-V	Show version
-VV	Show version number only
-h	Help

History

Started as a hobby project in 1988. Version 0.1 dates from 1994 — a DOS program with colored ASCII board and conio.h. First victory against its creator in a memorable presentation to Computer Science classmates at UNESP. Grew from 1,381 lines to a peak of 5,550 (v5.8, 2013), then refactored down to ~3,800 lines (v9.0, 2026). Played on FICS (2013-2018), Lichess (2018-present). UCI support added in v8.0 (2026), replacing the XBoard protocol used since v2.0 (2004).

License

GNU General Public License v2. See COPYING.

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Have Fun!

Bom divertimento!

Beco.