The answer is the centralized power of the shogunate had collapsed. The Late Tokugawa Shogunate was the era between 1853 and 1867, through which Japan finished its nationalist foreign policy named sakoku and restructured from a feudal shogunate to the Meiji government. The chief philosophical and partisan parties during this era were separated into the pro-imperialist and the shogunate force. Though these two groups were the most noticeable influences, many other groups tried to use the disorder of the Bakumatsu period to grab individual power.
