Why was South Korea’s military unprepared when the Korean War began?

When the Korean War began in June 1950, South Korea was significantly unprepared to resist a full-scale invasion due to several critical factors:

• Limited Military Capacity: By June 1950, the South Korean force consisted of only 98,000 troops equipped primarily with small arms, which were sufficient only for internal security and minor border skirmishes rather than conventional warfare.1
• Inadequate Training and Readiness: Internal partisan warfare throughout the late 1940s diverted resources and delayed the formal training of the Republic of Korea Army. By early 1950, American advisers assessed that fewer than half of the army's infantry battalions were even marginally prepared for combat.2
• Logistical Delays: Although the United States had approved military aid, the promised equipment was still in transit when the North Korean invasion commenced. U.S. assistance prior to the war had consisted largely of surplus light weapons and supplies.12
• Superior North Korean Preparation: In contrast, North Korean forces were far better equipped and trained, bolstered by heavy military equipment from the Soviet Union and experienced troops transferred from China.1