The natural harbour and commercial city at the mouth of the Urakami River already had a long history of interaction with Europe, China and Southeast Asia. Throughout the Japanese isolation period (1639-1854) Dutch traders were the principal foreign power permitted to remain in Japan, being confined to the tiny island of Dejima. In 1854, the Tokugawa Shogunate's response to Perry's visit was to build a navy. They lifted the ban on building large ships and established the Nagasaki Naval Training Institute and Nagasaki Foundry. Following on from the Shogunate's foundations, Mitsubishi's shipyard turned out many of Japan's greatest vessels. The company also pioneered its undersea coal mines, the first to be developed with Western technology, and which supported the global naval and commercial network of steamships operating in East Asia and the Pacific.