Chinese annual imports were reduced to the value of 22.5 tons of silver (by which Chinese could export 1,800 tons of Japanese copper), and the Dutch at only half those figures. Silver then was replaced by copper as the principal Japanese export from Nagasaki, yet by the time Japanese opened its doors to foreign trade in 1854, it would have substantial products of its own like silk yarn, tea, and marine products to export.

      Let me explain this economic transformation by focusing on the development of three new Japanese export products-sugar production, silk goods, and cotton goods-all previously imported from China. In the early eighteenth century, the shogunate enforced restrictions on the import of sugar. At this time, annual sugar imports from China totaled as much as 3 million kilograms, but thanks to conscious government support, domestic sugar production rapidly developed. Chinese methods of sugarcane planting, crystallizing sugar from sugar juice, and making stone and wooden sugar pressing machines were carefully investigated by government officials at Nagasaki and then published for general consumption. The result was extensive planting of sugarcane in the Okinawas and parts of Kyushu and thus by the end of the eighteenth century a reduction of the annual sugar imports from China to a half or even third of their level a century earlier.

     In contrast to the active role of government support of sugar and its reliance merely on Chinese printed books, one can readily discern the importance of private entrepreneurship and reliance on foreign experts for the development of the silk and cotton industries during the Tokugawa period.

     Chinese silk had for centuries been a highly sought import in Japan. But the mid-sixteenth century saw a great increase, with the annual import of 60,000 to 150,000 kilograms of Chinese raw silk on Portuguese boats. Soon this amount multiplied to about 200,000 kilograms in 1615 and between 180,000 and 240,000 kilograms in the 1630s. In the words of one Spanish trader who stayed in Nagasaki for 20 years during this period, the Japanese were in love with silk. As he wrote in the early seventeenth century: