Sakoku

The central motive was the fear of Christianity. By 1600 there were perhaps a few hundred thousand Japanese Christians, and the shogunate saw the missionaries and their Iberian patrons as a threat to its authority and to the loyalty of daimyō in western Japan. Christianity was banned in 1614. The Shimabara Rebellion of 1637–1638, a revolt of peasants and masterless samurai in Kyushu with a strong Christian identity, confirmed these fears and led directly to the expulsion of the Portuguese in 1639.

A second motive was control: by monopolising foreign relations and trade, the shogunate prevented powerful western daimyō from enriching themselves through overseas commerce and forming foreign alliances. The Protestant Dutch, who made clear that they came only to trade and not to proselytise, were allowed to stay.

Foreign relations ran through four 'gateways' (yottsu no kuchi), each managed differently. At Nagasaki, under direct shogunal control, the Dutch East India Company traded from the artificial island of Dejima, and Chinese merchants, after 1689 confined to a walled Chinese quarter, carried on a larger trade. The Sō family of Tsushima conducted relations and trade with Joseon Korea, which sent twelve diplomatic missions (tsūshinshi) to Japan between 1607 and 1811. The Shimazu lords of Satsuma, who had invaded the Ryukyu Kingdom in 1609, controlled its trade while Ryukyu continued to send tribute to China. The Matsumae domain in southern Hokkaido monopolised trade with the Ainu.

Through these channels Japan imported Chinese silk, sugar, medicines and books and exported silver, copper, porcelain and marine products. Many historians therefore prefer the term kaikin, 'maritime prohibitions', used for similar policies in Ming and Qing China, and Japanese textbooks now often put 'sakoku' in quotation marks.

The Dutch at Dejima were Japan's window on Europe. Each year the head of the trading post travelled to Edo to pay respects to the shōgun, and the Dutch submitted reports on world events (fūsetsugaki). From the eighteenth century Japanese scholars studied Western medicine, astronomy, botany and geography through Dutch books – a field known as rangaku, 'Dutch learning'. The translation of a Dutch anatomy text as Kaitai Shinsho in 1774 marked its breakthrough.

Two of the most important European observers were Germans in Dutch service. Engelbert Kaempfer of Lemgo, physician at Dejima in 1690–1692, wrote the History of Japan, published posthumously in English in 1727; it was his description of Japan's closure that the interpreter Shizuki Tadao translated in 1801, coining the word sakoku. Philipp Franz von Siebold of Würzburg, who arrived in 1823, taught medicine to Japanese students at his Narutaki school in Nagasaki and assembled large collections; his expulsion in 1829 after being found with forbidden maps became known as the Siebold Incident.

From the late eighteenth century foreign ships appeared more often. Russian envoys arrived in 1792 and 1804 seeking trade, a British warship forced its way into Nagasaki harbour in 1808, and whalers visited the coasts. In 1825 the shogunate ordered that foreign ships be driven off by force, an order it relaxed in 1842 after learning of China's defeat in the Opium War. Japanese castaways such as Nakahama Manjirō, who lived in the United States before returning in 1851, brought back first-hand knowledge of the West.

In July 1853 Commodore Matthew Perry of the United States Navy arrived at Uraga with four ships and a letter demanding that Japan open its ports. He returned in 1854, and the shogunate signed the Treaty of Kanagawa, opening Shimoda and Hakodate to American ships. Similar treaties with Britain, Russia and the Netherlands followed. The Harris Treaty of 1858 and parallel agreements with other powers opened Yokohama, Nagasaki, Hakodate, and later Kobe and Niigata, to trade, with fixed tariffs and extraterritoriality for foreigners. The crisis over these unequal treaties contributed decisively to the fall of the shogunate.

The effects of sakoku are debated. Older accounts blamed it for Japan's technological lag behind the West; others credit it with more than two centuries of peace, the growth of a self-sufficient domestic economy and the flowering of Edo culture. The image of a 'closed' Japan was also shaped by the Meiji government, which contrasted its own opening with Tokugawa backwardness. What is clear is that when the country opened, a small but well-informed group of scholars and officials already understood much about the Western world – one reason Japan could adapt so quickly after 1868.