Unsolved Problems in Go

[SmoothOper]

Igo Hatsuyoron is cool. I was thinking that there would be smaller versions, where a groups status couldn't be known due to permutations in order of play. I think they would have to be bigger than 7x7 since those have been solved by computer. I suppose I would also be interested in tsumego that computers solved by computer that were extremely difficult, though I am not sure difficult for a computer means the same as for a person. Have any pro's used computers to develop especially difficult tesuji to refute?

[csobod]

Any unsolved problem is only because ... the problem is too open ended (IE that igohatsu book having a 100+ move variation, cant be sure of answer).

Igo Hatsuyoron 120 is not "too open ended" at all.

The solution consist of three phases.

Phase 1 (approximately 70 moves long) is preparing the ground. This is the creation of the Hanezeki, including the building of the Hanezeki's tail. If we let aside really wrong moves for variations, it is possible to make some smaller, but not really decisive mistakes (i.e. non-optimal moves), which effect will be shown in phase 3.

Phase 2 if about finding the Guzumi or not (in this case Black will lose). And about White's best answer to the Guzumi (neither of which will lead to a White win). This phase is only two moves long, but extremely complex, because of the large amount of possible variations. And so far, nobody, even no professional, has found a refutation of the Guzumi.

Phase 3 (a further 100 moves until the end; endgame only) is harvesting the fruits. Nothing really decisive can happen here that would affect the outcome of the game (if we let aside really wrong moves again). And again, there is the chance of making some non-optimal, but non-decisive moves.

So the real problem of the problem is the situation before the Guzumi in the top right corner. We have been told by professionals that the Guzumi were a typical endgame move, which "usually" comes into mind automatically.

Thanks for breaking that down! I was just musing on it the other week with some chums.