Yasuko retcon suggestion: Myoshiman Colony
by Marc SaindonI've posted about Yasuko maybe 4 years ago, but re-thinking about it, rather than find the origin of M-Japan (being a Ochalea spin-off isn't sufficient), I think it works better as a Rakasta colony from Myoshima that welcomed human refugees who took work as fishermen and farmers, while the Catfolk took on noble and military roles. The humans adopted the Myoshiman language as their own, althout the rakasta took Ochalean writing.
The 'Yasuko Tribal lands' can be reworked as a missed translation (like in the Princess Ark or the recent Glen Welch video on the Hinterlands), and it's more 'Yasuko Feudal Clans'. The cats, of course, have spelljammer magitech to keep contact and trade with Pa(n)tera, Mystara's invisible asian cat moon.
Yasuko map
Source: https://www.boredpanda.com/samurai-cat-collection/