Interesting but it does get me too excited. It is about as useful as calculating pi to more than 100 digits.

I was interested to see that they define a valid position as one in which every chain of stones of one color is adjacent to an empty point. It's not clear to me that every such position could actually arise as a result of a sequence of valid moves starting with an empty board.

It's not clear to me that every such position could actually arise as a result of a sequence of valid moves starting with an empty board.

Due to its capture rule, the positions that can arise in a game of Go are exactly the legal positions.

I was indeed surprised a mathematician such as DrStraw would complain about lack of usefulness, but then maybe he is a grumpy old man first and a mathematician second .

P.S. I don't think there's many instances where you'd need pi to even that precision. IIRC you need about 40 digits to calculate the size of the observable universe to the accuracy of an atom, so unless you were calculating something with powers of pi (which is not so common) to increase the error then 100 is more than you need.

Remember that passing is a legal move, too, so between placing stones, captures, and passing you can pretty easily reach any legal board state.

(And Robert beat me to the punch.)

Mathematics is about expanding knowledge, you should know that.

It doesn't account for rotations--all rotated versions are counted as separate positions. The odd number is because the empty board is legal, but the full board is not.

Tromp posted the number ca. 2 years ago, after ca. 20 years of his research in the topic.

P.S. I don't think there's many instances where you'd need pi to even that precision. IIRC you need about 40 digits to calculate the size of the observable universe to the accuracy of an atom, so unless you were calculating something with powers of pi (which is not so common) to increase the error then 100 is more than you need.