Past Events of the Shogunate

Our neighbor once had a past where the rulers were unable to govern! But at that time, a brand new regime emerged! That's right, that was the birth of the shogunate! And how powerful was the shogunate at that time? We all know it! But why did such a powerful shogunate eventually decline? It's up to me to tell you what happened before the shogunate fell. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.