I loved this. (Did you post it on LJ before? If you did, I'm terribly sorry to have missed reading it.)
The focus on the goban and on Sai and Torajirou is refreshing, and I like the dispassionate tone you have here. It suits the way you examine the de-humanising (?) effect of that much Go (and Sai) on Torajirou, and connects with the fact that Sai is a ghost and, er, not human.
The details you weave into this fic are great; Sai in his own time, the jubango, the mention of the other pros. Brilliant.