Author: Petr Baudis, Jean-loup Gailly
License: GPLv2
Price: none (aug.'16)
Category: engine
Operating system: Wind., Linux, Mac, Android
Stable Version: 12.10/Jowa (aug.'18)
Development status: active
Programming language: C
Homepage: [ext]
Can connect itself by GTP: yes
Strongest play: 4d (sept.'12)
Plays online: pachi2 (KGS, read info!)
Infos last checked:

Pachi is an open source go playing program (engine) or go-bot. It is being actively developed, although it has fallen behind strength-wise compared to top engines.

It reached 4d on kgs server (account Pachi2 cluster version) and also runs well on lightweight hardware (raspberry pi, 2d). dcnn support doesn't require a gpu.

See latest go software updates for the latest update news.

Homepage is at [ext]
(see also [ext] for previous versions).

The source code, written in C, is available on [ext] github.

Windows binaries are available in the [ext] release section.

Mac binary is available in the Sente Goban extension [ext] package.

Android: Pachi version 10.00 with ElyGo frontend: [ext] play store [ext] source

The successive versions of the program are named after famous Japanese players:

Pachi 2.00  September 2008  Sana?
Pachi 3.00    October 2009  Sanetsu
Pachi 4.00    October 2009  Doetsu
Pachi 5.00   Februari 2010  Dosaku
Pachi 8.00        May 2011  Shuhaku
Pachi 9.00    October 2011  Hakugen
Pachi 10.00    August 2012  Satsugen
Pachi 11.00     April 2015  Retsugen
Pachi 12.00   January 2018  Jowa

How to use Pachi on Windows: See readme in windows release.
(instructions in Russian for older release): [ext]

You can also check out the derivatives:

Mentions in Literature

In Reinforcement Learning with Tensor Flow by [ext] Sayon Dutta (ISBN: 9781788835725), Pachi is incorrectly described as the strongest AI in the pre AlphaGo era "The AI programs of Go before AlphaGo totally relied on Monte Carlo Tree Search. These were Fuego, Pachi, Zen, and Crazy Stone. Out of which, Pachi was the strongest until AlphaGo defeated it using only policy network without using any search methods."

Pachi last edited by 2a01:0e0a:026a:0bc0 on November 20, 2019 - 21:30
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