On January 25, 1950, after a series of cautious reconnaissance advances, the U.S. 8th Army, under the command of Gen Matthew Ridgway, initiated Operation Thunderbolt, a major attack against Chinese and North Korean forces near the Han River.

The goal of Operation Thunderbolt was to inflict maximum punishment on the enemy while keeping major UN units intact. 

GEN Ridgway stressed “good footwork combined with firepower.” 8th Army forces did not advance beyond carefully planned  “phase lines” until every assigned unit reached it. 

After Operation Thunderbolt secured the southern bank of the Han River, the Chinese and North Korean forces moved their operations further east.

In an attempt to regain the initiative, the Chinese counterattacked at the Battle of Hoengsong on February 11, briefly stopping US X Corps’ advance. However, without rest and recuperation, the new Communist offensive faded at the Battle of Chipyong-ni on February 15.

On February 21, 1950, with Communist forces incapable of further offensive operations, GEN Ridgway ordered Operation Killer to eliminate the remainder of Chinese and North Korean forces in the area.