Though much reduced by efforts of the 1st Marine Division until mid-February and the ROK 2nd Division thereafter to destroy the unit in the Pohang-Andong-Yongdok area, the division had maintained a formal organization of a headquarters and three regiments and with a surviving strength of about two thousand had managed by the opening of Operation Ripper to slip north through the Taebaek Mountains to the Irwol Mountain region, 30 miles northeast of Andong.