Japanese warlords are so weird. Or at least, as depicted in this Manga. They always have all their remaining retainers fight to the last man, while they head to the back of room by themselves and commit Seppuku. And the warlords all know that the loser will always try to kill themselves to most likely avoid a fate worse than death once it's checkmate. So, why can't both sides at least let all the remaining low ranking soldiers go back to their families and become simple farmers, so less people die, while the winner agrees to give the loser 10 minutes to kill himself in peace?