[News] Number of legal 18X18 positions computed

Researcher John Tromp recently finished computing the number of legal positions on a 18X18 go board. It took 9 months of computations and 4 petabytes of disk I/O. He’s working on 19X19 now.

More information here: http://tromp.github.io/go/legal.html

For reference, here’s the number: 669723114288829212892740188841706543509937780640178732810318337696945624428547218105214326012774371397184848890970111836283470468812827907149926502347633, or ~6.6972e+152


Interesting, I did not realize that the number of legal positions on 19x19 had not yet been computed and that we are so close to the point in history when it will first become exactly known.

It seems that the team has also computed the number of legal positions on the 19x18 board.