This is wrong, Seika is active:
Seika is active in south eastern Zhao in some form. We don’t know against who but it is specifically said by Riboku himself that Seika is not an inactive army but was specifically fighting some force. In the same way Ouki was still actively fighting battles for Qin but not fighting any of the other states most likely.
So no, Shibashou is not some dude sitting inside of Seika doing nothing lol.
And Shibashou being nominated for the 3GH rank solely by virtue of his martial prowess puts an end to any delusions of Renpa being able to match this guy on flat land lol. Shibashou isn’t Houken, he is an active general and lord of his own city just like Ouki, not some forest hobo like Houken lol.