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 as Mount Auckland. Hallasan is written in North Korea in Chosungul as if it were "Hannasan" (한나산); however, it is still pronounced as "Hallasan". In the past, Hallasan has been known by numerous other names in Korean including "Buak" (부악/), "Wonsan" (원산/), "Jinsan" (진산/), "Seonsan" (선산/), "Dumuak" (두무악/), "Burasan" (부라산/), "Yeongjusan" 영주산(), and "Hyeolmangbong" (혈망봉/). Every name of Hallasan has meanings and legends. "Han" represents the universe, and "la" means "pull". Both words mean that the mountain is high enough to pull the universe. According to the old legend, if anyone were to climb up the mountain, see a star