| format | 15-round Swiss |
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| board size | 19×19 |
| rules | Chinese |
| komi | 7½ |
| time | Four hours each, sudden death |
The first round started at 22:00 UTC on the evening of Sunday 21st.
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In the table above, The numbers in this table may not add up as you expect. This is because the "Wins" column incudes byes. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
The results were clear, as shown by the cross-table above. Zen19S won all its games, while pachi2 won all its games except those against Zen19S.
When pachi2 is playing on KGS, it is possible to "chat" to it, by saying winrate. It responds by stating its current assessment of its probability of winning. However KGS does not allow ordinary users to chat to a player who in a tournament, only admins can do this. So, as a KGS admin, I sometimes asked pachi2 for its winrate, and reported the result in the game chat.
In round 5, pachi2 had a won position against Orego12 when I did this. It responded In 534069 playouts at 64 machines, white O11 can win with 100.51% probability. As an assessment of its chances in that game, this was accurate enough; but it shows that it does not calculate these percentages quite as you might expect. Its operator Jean-loup Gailly has explained "There can be several reasons for this. On a single machine, statistics are updated by multiple threads in parallel without locking because locking is too costly. In distributed mode, statistics received from other machines are also added without locking."
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| AyaMC vs ManyFaces1 |
| Moves 105-114. |
In its round 6 game with AyaMC, ManyFaces1 as Black attacked a weak white group, as shown to the right. AyaMC responded effectively, saving its group and killing the attacking stones. This produced a big gain, and AyaMC won the game.
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| StoneGrid vs pachi2 |
| Moves 50-66. |
In pachi2's round 9 game with StoneGrid, it played out part of a losing ladder, as shown to the left. As it did so, its "winrate" dropped steadily, from 57% after move 49, to 39% after move 65. However it was able to recover from this large loss, and win the game.
Round 9 was also Zen19S's first (and only) bye. Its operator Hideki Kato had been waiting for a bye, as an opportunity to integrate a new 4-core computer with Zen19S's existing hardware. But as the draw for round 9 was made at midnight in Japan, he may have preferred to sleep. I believe he did add the new computer some time before round 12.
In round 12, Zen19S did not show up for its game with pachi2. While we were waiting for Zen19S, I asked pachi2 "winrate", and it answered "In 0 playouts at 46 machines, none can win with 100.00% probability". The "0", the "none", and the "100.00%" are all reasonable in the circumstances of a game which has not yet started; but the "46" is worrying. Pachi2 was meant to be using 64 machines. Its operator Jean-loup Gailly later learned that some of them had stopped working properly.
Zen19S eventually joined this game, with only 32½ minutes left on its clock, whicl pachi2 still had four hours. Zen19S was still able to play well enough to win.
In the round 15 game between Zen19S and gomorra3, the kibitzers' view was that gomorra3 was ahead for some of the game.
The players receive points for the 2011 Annual KGS Bot Championship as follows:
| Zen | 8 |
| pachi | 5 |
| Aya | 2 |
| gomorra | 2 |
| Many Faces of Go | 2 |