On 2017-12-14 at 8:59 PM, Manchu said:Kachiko has motive, means, and opportunity. The only reason I don't suspect her is because she's such an obvious suspect!
I feel like it should have come up in Kachiko's internal monologue if she knew anything about Satsume's death. I'd actually put more stock in Toshimoko being behind it... and I don't believe that either, mostly because I suspect he would have challenged Satsume to a duel and killed him that way.
I think looking at political motives is pointless; like you said, there isn't any other Clan which wouldn't benefit from Satsume's death, since it gives the other Clans a shot at the Emerald Championship. We need to look at personalities here, rather than Clans, and that leaves very few people - none of the people we've seen in the story thus far has given any hints they know how Satsume died.
Edited by Mangod