Inspired by @bugcat’s OGS proverb and especially from playing a lot of 9x9, I’ve become interested in whether a lone stone at 3-3 can make territory or be killed, depending on nearby threats. For example, I would expect to kill Black in this position:
If Black plays first at the marked point instead, his stones will live. Often the outcome seems obvious (to me at 8 kyu), but sometimes it’s unclear, so I was thinking that a good way to get stronger would be to systematically learn a bunch of the cases.
I haven’t found any catalogs of these situations online, so I thought about trying to analyze them with AI. I downloaded Lizzie and set up this framework where White wins by only 2.5 points if black fails to invade the upper-left corner:
This means if Black can secure even a tiny bit of territory there, he can win. There’s also nothing else interesting to do anywhere else on the board, which should help focus attention on that corner. Note that I don’t know what I’m doing. Is there a more straightforward way to approach corner problems with AI?
Anyway, with this setup, KataGo correctly evaluates the position above as hopeless for Black:
But with one of the white stones moved two steps away, the game swings completely in Black’s favor:
What surprises me is that with the stone at the intermediate point, KataGo is undecided on the result:
Leela Zero gives a similarly inconclusive result, ~70% favorable to black. Even after a million playouts it’s apparently unclear whether that stone is alive or dead. Is this real or just an artifact of my contrived setup? Some of the playouts do seem to involve ladder-like formations:
So maybe the AI is not very good at working with such thick and distant walls? Or is this actually an unsolved position? Again, I don’t know what I’m doing here. Is this interesting at all? Anyone have any pointers or other feedback?