What happened
Toyotomi Hideyoshi launched two invasions of Korea, in 1592 and 1597. Japanese armies took Seoul within weeks of the first landing and drove far north. The Japanese withdrew after Hideyoshi’s death in 1598; Admiral Yi Sun-sin fell in the final battle at Noryang.
Background
The war turned on three forces. Yi Sun-sin’s navy severed Japanese supply lines — at Hansando in 1592, and at Myeongnyang in 1597, where he fought with thirteen ships against a fleet traditionally counted at well over a hundred. Ming China intervened on Korea’s side. And Korean “righteous army” guerrillas harried the invaders throughout.
Consequences
The costs to Korea were immense: enormous loss of life, farmland ruined, palaces and archives burned, and artisans — notably potters — taken to Japan. Joseon-Japan relations were restored from 1609 with periodic Korean embassies. The war is remembered differently in each country; this page states the documented record.