The coming of the West in Tokugawa Japan in the 1850s has great impact in both internal and external developments of Japanese history.

End of seclusion policy -- the traditional foreign policy of Tokugawa Japan was sakoku under which the whole of Japan was dosed to foreign influence except a few Dutch and Chinese traders in Nagasaki. Unable to resist the forceful intrusion of the West, the Tokugawas had to open the country and sign unequal treaties with the western nations in the 1850s. But this opening of the country was only the first stage because in the forthcoming Meiji era the Japanese accepted to a great extent what the West could offer them in various aspects. A drastic westernization process was to come since the fall of the Tokugawa bakufu.

Socio-economic impact -- internally, the Tokugawa society was already experiencing socio-economic changes. These changes, mostly undesired by the shogunate, were intensified with the coming of the West. For instance, under cover of the unequal treaties, foreign imports flooded into Japan and foreigners travelled inland for various reasons. Economically, the total value of foreign trade fluctuated, but on the whole increased. Imports rose from 7 million dollars (1864) to over 18 million (1867). Inflation ran wild, as evidenced from the 3 to 4 times increase in the price of rice in the l860s. Socially, attacks and murders of foreigners and legations were prevalent since 1859. The death of Charles Richardson in Satsuma in 1862 created a crisis in which Satsuma was defeated by the British squadron. In short, the joi movement was in full swing in the early 1860s when socio-economic impact of the West aggravated the hardship of the Japanese people.

Political impact -- the coming of the West had far-reaching political impact. The final outcome was the downfall of the Tokugawa shogunate by 1868.
The bakufu had been confronted with a number of difficulties in the early 19th century. Yet its inability to cope with these difficulties was only exposed with the coming of the West.
To take an example, the lack of leadership and strength of the shogunate was disclosed when it sought advice from the daimyo upon the acceptance or refusalof Perry's terms. Of course, this act was interpreted as a confession of bakufu weaknesses and indecision. Even worse, the bakufu sought imperial sanction to the draft treaty with Harris in 1858. These two mistakes, that of consulting the feudal lords in 1853, and of seeking imperial sanction in 1858, were fatal to the bakufu because they made public its lack of leadership, confidence and power at a time of national crisis.
To take another example, the coming of the West enhanced the influence and power of the tozama daimyo and the emperor. The foreign intrusion gave an excuse for the feudal lords, especially the tozama, to carry out military reforms and other activities harmful to the shogunate's interest. Moreover, the bakufu acted too slowly and let the initiative in modernization fall into the hands of a few domains whose reforms in the 1840s had made such developments possible. As a result, the gap between them and the Tokugawas, already reduced by economic changes, was narrowed further. Tokugawa's military establishment was soon brought to a level only slightly above that of its potential enemies. By 1866, all alliance between Satsuma and Choshu was enough to challenge successfully the authority of the Tokugawa shogunate.
At the same time, prestige of the emperor, already enhanced by intellectual changes in Japan, was growing rapidly in late Tokugawa politics. That the bakufu sought imperial sanction to treaties with the West was an example. Furthermore, only unwillingly and under pressure did Emperor Komei agree to ratify the treaties in 1859. Finally, in 1862 the Kyoto Court was bold enough to issue an edict to the Shogun instructing him to set about the expulsion of the foreigners in the following year. All these acts were unthinkable in the golden days of Tokugawa rule. But with its confession of weaknesses, both the daimyo and the tenno took advantage to challenge the shogun's rule of Japan.

Sonno-joi movement -- the coming of the West created the sonno-joi movement in the 1860s. The more than two centuries of seclusion had nursed an anti-foreign sentiment in many Japanese minds. Furthermore, as we have seen, the western impact aggravated their socio-economic difficulties. Therefore, many resorted to the "joi" movement. This expressed itself in the attacks on individual foreigners as well as the Satsuma-Choshu wars with the West in 1863-4. The westerners took revenge and defeated both Satsuma and Choshu. Thus ended the joi movement. Instead, a sense of realism was spread among the more understanding samurai dass. Accommodation with and learning from the West began to take shape and so originated the Meiji modernization.
Meanwhile, the inability of the bakufu to face the national crisis caused many to turn to the emperor as the symbol of unity for salvation. The "sonno" movement was championed by all anti-Tokugawa forces, represented by the Satcho-Hito combination.
Both Emperors Komei and Meiji were honoured and the "Kinno-Tabaku" movement succeeded in overthrowing the usurper -- the Tokugawa Shogun in 1868. An imperial restoration (Meiji Restoration) followed.

Foreign intervention in domestic politics -- in the last few years of political struggle, both the British and French meddled in Japan's politics. In simple terms, the British supported the anti-Tokugawa tozama daimyo, especially Satsuma. The French assisted the bakufu in a self-strengthening effort. Such foreign intervention might lead to prolonged civil war in Japan, but Shogun Keiki decided not to resist and surrender voluntarily his domain to Emperor Meiji.

Conclusion -- the coming of the West ended the seclusion policy of the Tokugawa shogunate. Internally, it intensified all those existing changes in Japan which were detrimental to the Tokugawa rule. The final outcome was the Meiji Restoration.