10. Historical Figure_Admiral Yi Sun-sin Yi Sun-sin was a heroic naval commander, who saved the country from national crisis during the Imjin War (1592-1598). Japan’s invasion of Korea came as a surprise to most officials in Joseon. However, Yi foresaw Japan’s ambitions and made full preparations for potential attacks. He led all his battles to victory and turned the war situation in favor of Joseon. Korean people admire Admiral Yi Sun-sin.