Human vs AI in Go in 2026: Lessons for superintelligence?

In July 2026, Korean Go player Shin Jin-seo defeated KataGo 2-1, with only[1] a 2-stone handicap (favoring Shin). I thought this was very surprising, and posted on LessWrong and Twitter asking how to interpret this. I didn’t get any entirely satisfactory answer, so I decided to spend ~one day looking into it and writing up my understanding.To preface this post: I don’t know all that much about Go and I'm a quite bad Go player (like, no better than 20 kyu or something like that). But in 2022 I di...