The Japanese Invasion was a war between Joseon and Japan from 1592 to 1598 (7 years). Toyotomi Hideyoshi of Japan invaded Joseon after unifying his country. Then king, Seonjo, fled to the north. But as the Joseon's army, including Yi Sun-sin, fought hard, Japan retreated for a while. Japan invaded again in 1597, and the war ended when Toyotomi Hideyoshi died. 