The beginning of Japan's period of isolation from the world is marked by the sakoku policy, formally established in 1635. Under this policy, the Tokugawa shogunate implemented strict regulations that curtailed foreign influence and prohibited Japanese citizens from traveling abroad. The intent was to preserve Japanese culture and maintain social order, fearing the destabilizing effects of foreign ideas, particularly Christianity. During this time, Japan limited trade mainly to the Dutch and Chinese, who were allowed to operate in the port of Nagasaki. This isolation lasted for over two centuries until Commodore Matthew Perry's arrival in 1853, which forced Japan to open its borders to international trade.