hmmm..well, I'm no expert, but all things being equal, the Romans. Granted, we don;t have enough info, but a (different periods, really) standard, game-style "balanced" army comprising of some some archers, ashi, yari-spear, etc. with a few elites (one or two units of monks or heavy cav) vs. a similar of Roman (a few archers, some spear, some cav, maybe a few chariot) and the Romans with their "wall of steel" would handle anything but lots of teppo/muskets.