What were the Japanese invasions of Korea?
Between 1592 and 1598 Toyotomi Hideyoshi sent large armies to invade Korea, with the declared intention of going on to conquer Ming China. The wars are known in Japan as the Bunroku and Keicho campaigns, in Korea as the Imjin War, and in China as the Wanli Korean campaign.
They were a catastrophe. Enormous numbers of Korean civilians died, much of the peninsula was devastated, tens of thousands of people were taken to Japan, and Japan gained nothing. The armies withdrew when Hideyoshi died in 1598.
Why did it happen?
Hideyoshi's stated aim, set out in his own letters, was the conquest of Ming China, with Korea as the road to it and as a subordinate ally he expected to be granted passage by.
Historians have offered further explanations — occupying an enormous warrior class that had run out of domestic wars, redirecting the ambitions of newly subordinated daimyo, personal ambition after the completion of unification. None of these excludes the others, and the sources support the simple version: he intended to conquer, and he expected it to be quick.
Forces and sides
The first invasion involved roughly 150,000 Japanese troops; the second, roughly 140,000. Ming China committed forces that grew over the war into the tens of thousands.
Korean and Chinese casualty figures, and the number of civilians killed or taken, are not reliably known. The scale of the devastation, however, is not in dispute in any of the three national historiographies.
What happened?
In 1592 Japanese armies landed at Busan and advanced rapidly. Seoul fell within three weeks and Pyongyang within two months. Korean field armies were badly outmatched at first, particularly by Japanese firearms.
Three things then stopped the advance. The Korean navy under Yi Sun-sin repeatedly destroyed Japanese supply convoys, breaking the sea route north. Local Korean irregular forces, the "righteous armies", attacked the extended supply lines inland. And Ming China intervened in force, retaking Pyongyang in early 1593.
A long negotiation followed, conducted by intermediaries who misrepresented each side's terms to the other. When the deception was exposed — Hideyoshi had been told China was submitting, while China had been told Hideyoshi was accepting vassal status — the war resumed in 1597.
The second campaign was confined largely to the southern provinces, and was marked by particularly severe treatment of the civilian population. Japanese forces withdrew in late 1598 after Hideyoshi's death, fighting a final naval action at Noryang in which Yi Sun-sin was killed.
Outcome
No territory changed hands. Korea was left with its agricultural base, population and administration severely damaged, and it took generations to recover.
In Japan, the war exhausted the treasury and deepened the split between the administrators around Ishida Mitsunari and the field commanders who had fought — a split that broke into open war at Battle of Sekigahara two years later.
Ming China, having committed heavily, was weakened in ways that contributed to its collapse decades later.
Why it mattered
For Japan, the Korean campaigns are the reason the Toyotomi regime was hollow when Hideyoshi died. The men who fought each other at Sekigahara had learned to hate each other in Korea.
For Korea, the war is a defining national trauma, and Yi Sun-sin is a national hero. Any English-language account of this period that treats the invasions only as an episode in Hideyoshi's career is telling a fraction of the story.
The forced transfer of Korean potters to Kyushu is one concrete legacy: several major Japanese ceramic traditions, including Arita and Satsuma ware, begin with craftsmen taken during these campaigns.
Japanese, Korean and Chinese sources differ substantially on the course of individual engagements and on numbers. This page describes the outline that all three broadly agree on and flags where they do not.
