The Yinping Crossing (阴平道) was Deng Ai’s march through the Yinping mountains in 263 during the Wei Conquest of Shu. The route was narrow, mountainous, and considered nearly impassable for an army; Shu had not defended it in strength. Deng Ai led a small force through the pass, reportedly having his men roll down the slopes in felt blankets where the path was too steep, and emerged at Jiangyou.
Impact
With Deng Ai on the Chengdu plain, Liu Shan’s court debated resistance or surrender. No relief force could reach the capital in time. Liu Shan surrendered to Deng Ai, and Shu Han ceased to exist. The crossing is one of the most celebrated examples of an unexpected line of advance in Chinese military history and sealed Deng Ai’s reputation as a bold commander.