In 1854, Commodore Matthew Perry and the "Black Ships" of the United States Navy forced the opening of Japan to the outside world with the Convention of Kanagawa. Subsequent similar treaties with other Western countries brought economic and political crises. The resignation of the ''shōgun'' led to the Boshin War and the establishment of a centralized state nominally unified under the emperor (the Meiji Restoration). Adopting Western political, judicial, and military institutions, the Cabinet organized the Privy Council, introduced the Meiji Constitution, and assembled the Imperial Diet. During the Meiji era (1868–1912), the Empire of Japan emerged as the most developed nation in Asia and as an industrialized world power that pursued military conflict to expand its sphere of influence. After victories in the First Sino-Japanese War (1894–1895) and the Russo-Japanese War (1904–1905), Japan gained control of Taiwan, Korea and the southern half of Sakhalin. The Japanese population doubled from 35 million in 1873 to 70 million by 1935, with a significant shift to urbanization.