I'd guess those are the Taisho's standards/family member, depicting a general's unit heads that particular army. Nice to see the fan and parasol again but this is the SP campaign map and it looks much the same as M2TW in that respect.
Greg, I was one of those who requested the unit banners .... on the battlefield. Not 4 banners for honour 4 unit, 7 for H7 etc .. just banners, complete with mon for realism.