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Zen Computer Go Program Beats Takemiya With Just 4 Stones

Taking just a four-stone handicap on a full board, the Zen computer go program defeated Takemiya Masaki 9P on March 17. The legendary pro played two games against Zen as part of the 6th E&C Symposium in Japan. In the first game Zen received a five stone handicap and won by 11 points. After that the handicap was reduced to four stones, but Zen surprised many by winning again, this time by 20 points. Zen -- aka Zen19 -- was written by programmer Yoji Ojima and ran on hardware provided by Kato Hideki, of team DeepZen. According to Hideki, the hardware for this match was a mini-cluster of four PCs (a dual 6-core Xeon X5680/4.2 GHz, a 6-core Xeon W3680/4 GHz and two 4-core i7 920/3.5 GHz) connected via a GbE LAN. This is the same hardware used by Zen’s ‘zen19s’ and ‘zen19d’ accounts on KGS. Both of the games were played with 30 minutes main time and 60 seconds byo-yomi. Zen is currently ranked 5 dan when playing under similar time conditions on KGS. Earlier in the day, another pro, Ohashi Hirofumi 5P played two even games on 9×9 against Zen. The result was one win each. While winning against a pro with four stones is very impressive and shows how far computers have come in go, it’s clear that Zen was able to win these games by avoiding fighting to a certain extent and relying on its excellent positional judgement, raising the question of whether Zen and other programs will continue to improve steadily as the handicap is reduced and they’re forced to play a more risky style.
 - adapted from David Ormerod’s report on GoGameGuru, which includes both Takemiya-Zen game records. Photo: Takemiya Masaki 9P.