turn were expelled in 1638 for suspected complicity in the Christian rebellion, and when they sent an embassy to Japan two years later to seek the reopening of trade relations, the Japanese answered emphatically in the negative by executing the envoys.
The Tokugawa treatment of its own overseas traders and adventurers was just as severe as its treatment of foreign traders and missionaries in Japan. Fearing that overseas Japanese and traders traveling to foreign ports might bring back to Japan the Christian religion or dangerous foreign ideas, Edo decreed in 1636 that henceforth no Japanese was to go abroad and no Japanese resident abroad was to return to Japan. Two years later this decree was followed by another prohibiting the construction of large ships suitable for overseas trade, and as a result the native merchant marine was limited to small vessels for coastal commerce among the Japanese islands. The overseas expansion of the Japanese merchants was thus brought to an abrupt end, and thousands of Japanese abroad were permanently cut off from their homeland and left to lose their racial identity in the native population of the towns of Southeast Asia.
Despite this extremely reactionary policy of national isolation, the Tokugawa were wise enough not to cut off all contact with other nations. They preserved Nagasaki as a window looking out on the rest of the world. Chinese merchants were allowed to visit and trade there under careful supervision, and the Dutch trading post at Hirado was moved to a small island in Nagasaki harbor, where the Dutch merchants were kept in virtual year-round imprisonment.
