Commentary
The 21st Century Cup 2001 was hard-fought indeed. The top tier programs were quite evenly matched, and any of them could have won.
The entire tournament was run via GMP, with only minor glitches; next year we expect to require programs to implement a next-generation communications protocol which should make things run even more smoothly. In general, the tournament went smoothly, with six rounds being held successfully in the space of two afternoons.
My overwhelming impression was of a rapidly maturing group of go programs. The most bizarre sequence of the competition, namely a corner invasion at the 2-2 point which the opposing program attempted to answer at the 1-1 point, was the exception rather than the rule.
Michael Reiss' Go4++ won the championship, but only by a sum-of-defeated-opponents-scores tiebreak. Go4++ beat Haruka, the 1st runner-up, but and Haruka beat Wulu, the 2nd runner-up, but Wulu then turned around and beat Go4++, albeit by only a few points. Wulu's only loss, other than to Haruka, was to eigth-place GNU Go; without this loss, Haruka would have placed first and Wulu second. Of course, if Wulu had defeated Haruka, to which it lost by komi, it would have placed first.
There is no point in trying to rewrite history, but the conclusion remains the same: the top programs are very closely matched, and the second tier is moving up rapidly in strength.
(c) Intelligent Go Foundation