How did the end of Japan’s long isolation affect Japanese politics in the 1850s?

The end of Japan’s long isolation in the 1850s fundamentally destabilized the Tokugawa shogunate, triggering a political crisis that ultimately led to its collapse.

When Commodore Matthew C. Perry forced Japan to open its borders through the Treaty of Kanagawa (1854) and subsequent agreements, the shogunate’s inability to protect the country from foreign encroachment shattered its legitimacy. The shogun’s traditional role as the "barbarian-subduing generalissimo" was undermined, as the government made concessions to Western powers despite strong opposition from the imperial court in Kyoto.12

This tension fueled the rise of the "Sonnō jōi" movement—meaning "Revere the emperor! Drive out the barbarians!"—which activists used to challenge shogunal authority. As the shogunate struggled to balance national defense with internal political control, it faced increasing defiance from powerful domains like Chōshū and Satsuma. These domains eventually formed an alliance to overthrow the shogunate, leading to the Meiji Restoration in 1868 and the reestablishment of imperial rule.123