By US Center for Military History - http://www.history.army.mil/books/korea/maps/map23_full.jpg,
Mid-February 1951 perimeter defense engagement involving the 23d Infantry Regimental Combat Team (RCT) of the 2d Infantry Division and the Chinese People's Volunteer Army (CPVA, Chinese Communists) in and around the small village of Chipyong-ni about fifty miles east of Seoul.
The fighting at Chipyong-ni established that UN and U.S. forces could withstand anything and everything that the Communists could throw at them. The CPVA never again held the clear strategic initiative in the war.
taken from - Spencer C. Tucker et al., eds., Encyclopedia of the Korean War: A Political, Social, and Military History Volume I (Santa Barbara: ABC-CLIO, 2000), 142-143.