Yi San Hae was the Chief State Councilor when the Japanese invaded in 1592, beginning the Imjin War. After the defeats at Sangju and Tangeumdae, Seonjo expressed his wish to abandon the capital of Hanseong. This was opposed by all the government ministers except for Yi, who argued that there was a precedent in history for similar events. Blamed for the initial military setbacks and the loss of the capital, Yi was exiled to Kangwon Province until 1595. He was released in 1595 and returned to court despite opposition from the Westerners. During the war, to oppose Ryu Seong Ryong who supported Yi Sun Shin, Yi San Hae was more sympathetic towards Won Gyun. After his return he became Daejehak and acted as the leader of the Northerners although by this time they had divided into the greater Northerner and Smaller Northerners. Yi San Hae was part of the Greater Northerners but largely stayed out of inter factional squabbles.