One goal of Zheng He’s expeditions was to suppress piracy, which had become a problem all along the China coast. Already in the thirteenth century social disorder and banditry in Japan had expanded into seaborne banditry, some of it within the Japanese islands around the Inland Sea (Map 21.3), but also in the straits between Korea and Japan. Japanese “sea bandits” would raid the Korean coast, seizing rice and other goods to take home. In the sixteenth century bands several hundred strong would attack and loot Chinese coastal cities or hold them hostage for ransom. As maritime trade throughout East Asia grew more lively, sea bandits also took to attacking ships to steal their cargo. Although the pirates were called the “Japanese pirates” by both the Koreans and the Chinese, pirate gangs in fact recruited from all countries. The Ryūkyū (ryoo-kyoo) Islands and Taiwan became major bases.

Possibly encouraged by the exploits of these bandits, Hideyoshi, after his victories in unifying Japan, decided to extend his territory across the seas. In 1590, after receiving congratulations from Korea on his victories, Hideyoshi sent a letter asking the Koreans to allow his armies to pass through their country, declaring that his real target was China: “Disregarding the distance of the sea and mountain reaches that lie in between, I shall in one fell swoop invade Great Ming. I have in mind to introduce Japanese customs and values to the four hundred and more provinces of that country and bestow upon it the benefits of imperial rule and culture for the coming hundred million years.”3 He also sent demands for submission to countries of Southeast Asia and to the Spanish governor of the Philippines.

In 1592 Hideyoshi mobilized 158,000 soldiers and 9,200 sailors for his invasion and equipped them with muskets and cannon, which had recently been introduced into Japan. His forces overwhelmed Korean defenders and reached Seoul within three weeks and Pyongyang in two months. A few months later, in the middle of winter, Chinese armies arrived to help defend Korea, and Japanese forces were pushed back from Pyongyang. A stalemate remained in place until 1597, when Hideyoshi sent out new Japanese troops. This time the Ming army and the Korean navy were more successful in resisting the Japanese. In 1598, after Hideyoshi’s death, the Japanese army withdrew from Korea, but Korea was left devastated. (See “Listening to the Past: Keinen’s Poetic Diary of the Korea Campaign.”)

After recovering from the setbacks of these invasions, Korea began to advance socially and economically. During the Choso˘n Dynasty (1392–1910), the Korean elite (the yangban) turned away from Buddhism and toward strict Neo-Confucian orthodoxy. As agricultural productivity improved, the population grew from about 4.4 million in 1400 to about 8 million in 1600, 10 million in 1700, and 14 million in 1810 (or about half the size of Japan’s population and one-twentieth of China’s). With economic advances, slavery declined. When slaves ran away, landowners found that it was less expensive to replace them with sharecroppers than to recapture them. Between 1750 and 1790 the slave population dropped from 30 percent to 5 percent of the population. The hold of the yangban elite, however, remained strong. Through the eighteenth century about two dozen yangban families dominated the civil service examinations, leaving relatively few slots for commoners to rise to through study.