Pachi
Pachi is a open source go playing program or go-bot
the current version is
Pachi 5.0 Dosaku released in February 2010 see latest go software updates for the latest update news
The website http://chid0ri.deviantart.com/art/Pachi-the-bot-98877096 is given as home page but only shows some art.
The source code C++? is at http://repo.or.cz/w/pachi.git
Windows binaries are downloadable at http://gnugo.baduk.org/
The sucsessive 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