Battle of Triangle Hill

The Battle of Triangle Hill, also known as Operation Showdown or the Shangganling Campaign (Chinese: 上甘岭战役; pinyin: Shànggānlǐng Zhànyì), was a protracted military engagement during the Korean War. The main combatants were two United Nations (UN) infantry divisions, with additional support from the United States Air Force, against elements of the Chinese People's Volunteer Army (PVA) 15th and 12th Corps. The battle was part of UN attempts to gain control of the "Iron Triangle" and took place from 14 October to 25 November 1952.

The immediate UN objective was Triangle Hill (38°19′17″N 127°27′52″E), a forested ridge of high ground 2 kilometers (1.2 mi) north of Gimhwa-eup. The hill was occupied by the veterans of the PVA's 15th Corps. Over the course of nearly a month, substantial US and Republic of Korea Army (ROK) forces made repeated attempts to capture Triangle Hill and the adjacent Sniper Ridge. Despite clear superiority in artillery and aircraft, the escalating UN casualties resulted in the attack being halted after 42 days of fighting, with PVA forces regaining their original positions.