When American warships sailed into Tokyo Bay in 1853, Japan was facing an economic problem known as "Sakoku," which means "closed country." Japan had been isolated from the rest of the world for over 200 years, and it had strict policies in place that limited foreign trade and contact with outside cultures. The arrival of American ships threatened Japan's isolation by opening the country to foreign trade and exposing its weak economic system. Japan had to adapt quickly to this change to compete with other nations and maintain its sovereignty. This led to the Meiji Restoration in 1868, which modernized Japan's economy and established a strong industrial base.