Search results
Restart Arasan. This removes any settings in the Registry and will cause Arasan to start with default values, including board size and location. I want to distribute Arasan on a CDROM or in a magazine or though download. The Arasan chess GUI and chess engine binaries on this site are freely redistributable, provided that:
- Overview
- Copyright, license
- Program variants
- Command-line switches
- Option file (arasan.rc)
- UCI Options
- CECP options
- Neural Network
- Tablebases
- Programming and build information
Arasan is a chess engine, that is, a console-based program that plays the game of chess.
By itself, it has no graphical interface, but can be used together with interface programs such as Winboard and xboard. There is a separate Windows-only GUI for Arasan distributed with the Windows releases: it is not hosted on Github.
For communicating with a chess interface, Arasan supports either the standard CECP protocol (version 2) or the UCI protocol. CECP is the native protocol used by Winboard and xboard. UCI-compatible chess interfaces include ChessBase and Fritz. Arena, a free interface, supports both protocols.
Arasan is multi-platform (Windows, Linux, Mac OS, Unix) and supports multi-threading for higher performance.
Copyright 1994-2024 by Jon Dart. All Rights Reserved.
Arasan is licensed under the MIT License. See the LICENSE file.
Several different binaries for Arasan can be built. The default executable (arasanx-32 for 32-bit operating systems, or arasanx-64 for 64-bit ones) is designed to be runnable on most systems. Default x86 or x86_64 builds assume SSE2 instructions are available (these were introduced in 2000 with the Pentium IV).
Other program variants include:
1.arasanx-64-old - assumes no SIMD instructions, not even SSE2. Will run on very old x86 hardware.
2.arasanx-64-modern - requires a x86 processor with POPCNT, SSSE3 and SSE4.1 instructions (Intel Nehalem or later, i.e. 2008 era or more recent).
3.arasanx-64-avx2 - requires a more modern x86 processor with AVX2 instructions, as well as those required by the "modern" build. Recommended for AMD Excavator through Zen2 processors.
4.arasanx-64-avx2-bmi2 - requires a more modern x86 processor with AVX2 and BMI2 instructions, as well as those required by the "modern" build. Recommended for Intel Haswell or later processors and AMD processors on the Zen3 architecture (Nov. 2020) or later.
Arasanx recognizes the following command-line options:
•-H: specifies the hash table size in bytes ('K', 'M', or 'G' can be used to indicate kilobytes, megabyates or gigabytes).
•-c: specifies the number of threads to use (default is 1).
•-f: specifies a position file (FEN) to load on startup
•-t: shows some debugging output in the UI window or log file. To enable debug output, you also need to use the "-debugMode true" switch if using xboard/Winboard, or the "debug=true" option if using Arasan as a UCI engine. You normally shouldn't need to turn this on.
•-ics: outputs additional info when playing on a chess server.
Many aspects of Arasan's behavior can be modified by changing the arasan.rc file that is installed in the program directory. See comments in this file for details. If you do change it, I recommend retaining a backup copy so you can restore the default settings if you make a mistake or later decide you don't like your changes. You don't have to use ...
When used as a UCI engine, Arasan supports the following options:
•Hash - hash size in kilobytes
•Threads - number of threads to use
•Ponder - true to enable pondering (thinking on opponent's time)
•Contempt - followed by a number from -200 to 200. This is the inverse of the value of a draw in centipawns (1/100 pawn value). Negative values mean the opponent is higher rated, so a draw is desirable. Positive values mean the opponent is lower rated, so a draw should be avoided.
•Use tablebases - true to use tablebases, false to disable
Besides the standard option-setting commands such as "memory," the following additional option settings are available in CECP mode:
•Can resign - sets whether or not the engine can resign a game. Note: under UCI, the interface program is always in charge of resignation.
•Resign threshold - sets how bad the score must be before resignation. Only effective if "Can resign" is set true. Value is in centipawns (1/100 pawn) and is negative. So for example -500 means resign when down 5 pawns in score value.
•OwnBook - true to enable Arasan's native opening book, false to disable.
•BookPath - path to the Arasan book. Default is book.bin in the same directory as the Arasan engine executable.
•Favor frequent book moves - value from 0 to 100, default 50. Higher values favor selecting more frequent moves in the Arasan book.
Arasan now supports chess evaluation utilizing a neural network. The neural network file is external to the program and is loaded at runtime. The file name for the network can be specified using UCI or CECP options, or by setting the search.nnueFile option in the arasan.rc file. There is a default network filename set there. In the options, if no d...
Arasan supports Syzygy format compressed endgame tablebases. You can configure Arasan to use tablebases by editing the arasan.rc file, or by using a GUI that supports UCI or CECP option commands. Note that many chess GUIs will override the arasan.rc settings, and set their own defaults. So if using a GUI you should if possible set the tablebase path and related options in the GUI, not in the file.
The Arasan distribution does not come with any tablebase files. Syzygy tablebases can be downloaded from https://syzygy-tables.info/.
See BUILD.md for compilation instructions. See the Programmer's Guide for additional technical information.
Aug 7, 2020 · In version 6.0 and higher, the Arasan chess engine supports both Windows (32- or 64-bit versions) and other platforms such as Linux, but the Arasan GUI is still Windows-only. If you are not on Windows, you need to use a program such as xboard to view the chessboard and play games with Arasan. You can get xboard from.
Mar 10, 2006 · I have not changed the Arasan chess engine at all, so if you are using only the engine by itself (with a GUI such as Winboard, Arena, Fritz or Shredder), or if you are not on the Windows platform, there is no need to update.--Jon
Mar 10, 2006 · The Arasan GUI uses the 32-bit version of the engine and the UI will only let you set 1.5G for hash size.--Jon. Thank you for your answer Mr.Jon. I have a 64-bit ...
Click on one of the links below to download the latest version of Arasan. Note: if you have difficulty downloading a file, try right-click and then select "Save Link As ..". Note also: Windows XP is still supported, but you should have at least Service Pack 3 installed. Current engine source code is available on GitHub now (but official ...
People also ask
Does Arasan have a graphical interface?
Does Arasan chess work on Windows?
Does Arasan have a chess engine?
Are the Arasan chess GUI & Chess engine binaries free?
What is Arasan UI?
Does Arasan support Syzygy?
Mar 10, 2006 · Arasan 24.1 is available from https://www.arasanchess.org. Changes in Arasan 24.1: 1) Fix scoring for special case endgames (classical eval). 2) Add HCE scoring for KRN vs KR and KRB vs KR. 3) Fixes/tuning for strength reduction feature. 4) Add option to override opening book path. 5) Multiple fixes and updates to selfplay utility.
