Jeju uprising to Jeju from Busan and deploying police companies, each 1,700 strong, from the southern provinces of the mainland. The guerrillas retreated to their bases in the forests and caves around Hallasan, an extinct volcano and the highest mountain in South Korea. On April 29, the Korean, non-military, governor of Jeju province abandoned his post, defected, and joined the guerrillas. This caused many police officers, disillusioned by the atrocities they were ordered to commit against their own, to do the same. In response, U.S. military provincial governor William F. Dean ordered a purge of SKLP sympathizers from the ranks of the
Hallasan the mountain became Sanbangsan (산방산). Wonsan became the name of Hallasan because the center of the mountain is the highest point and the mountain looks like a circular cone. On a very clear day, Hanllasan is visible from the mainland. Yeongjusan was believed to be a habitat for a plant species that made people immortal. According to a legend, immortal wizards of Korea used to live in Hallasan. They were immortal because of this special plant. Qinshi Huang wanted the plant to live forever and ordered his men to get the plant (200 AD). Buak became the name of Hallasan,