Rangaku (Kyūjitai: /Shinjitai: , literally "Dutch learning", and by extension "Western learning") is a body of knowledge developed by Japan through its contacts with the Dutch enclave of Dejima, which allowed Japan to keep abreast of Western technology and medicine in the period when the country was closed to foreigners from 1641 to 1853 because of the Tokugawa shogunate's policy of national isolation (sakoku). Through Rangaku, some people in Japan learned many aspects of the scientific and technological revolution occurring in Europe at that time, helping the country build up the beginnings of a theoretical and technological scientific base, which helps to explain Japan's success in its radical and speedy modernization following the forced American opening of the country to foreign trade in 1854. History The Dutch traders at Dejima in Nagasaki were the only Europeans tolerated in Japan from 1639 until 1853 (the Dutch had a trading post in Hirado from 1609 till 1641 before they had to move to Dejima), and their movements were carefully watched and strictly controlled, being limited initially to one yearly trip to give their homage to the shōgun in Edo. They became instrumental, however, in transmitting to Japan some knowledge of the industrial and scientific revolution that was occurring in Europe: In 1720 the ban on Dutch books was lifted and the Japanese purchased and translated scientific books from the Dutch, obtained from them Western curiosities and manufactures (such as clocks, medical instruments, celestial and terrestrial globes, maps and plant seeds) and received demonstrations of Western innovations, including of electrical phenomena, as well as the flight of a hot air balloon in the early 19th century. While other European countries faced ideological and political battles associated with the Protestant Reformation, the Netherlands were a free state, attracting leading thinkers such as René Descartes. Altogether, thousands of such books were published, printed, and circulated. Japan had one of the largest urban populations in the world, with more than one million inhabitants in Edo, and many other large cities such as Osaka and Kyoto, offering a large, literate market to such novelties. In the large cities some shops, open to the general public, specialized in foreign curiosities. Beginnings (1640–1720) The first phase of Rangaku was quite limited and highly controlled. After the relocation of the Dutch trading post to Dejima, trade as well as the exchange of information and the activities of the remaining Westerners