Rangaku (: /: , 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, 1641–1853, 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 opening of the country to foreign trade in 1854.