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After the Incheon landing, the 1st Cavalry Division began its northward advance from the Pusan Perimeter. "Task Force Lynch" (after Lieutenant Colonel James H. Lynch), 3rd Battalion, 7th Cavalry Regiment, and two 70th Tank Battalion units (Charlie Company and the Intelligence–Reconnaissance Platoon) effected the "Pusan Perimeter Breakout" through 106.4 miles (171.2 km) of enemy territory to join the 7th Infantry Division at Osan. The X Corps rapidly defeated the KPA defenders around Seoul, thus threatening to trap the main KPA force in Southern Korea.

Who was defeated near Seoul, Korea?
the KPA