This society is a close agricultural civilization where vassals worked on fiefs owned by lords. In this system, the lords would receive a payment in terms of gold and produces that are nurtured by the vassals. Then, these Lords will then protect these people from invaders and thieves
Japan had instantly made enemies of all of Russia's allies. If your friend beat you up you wouldn't want to be his friend for a while and all of his friends may not like you after the fight.