Niangziguan (simplified Chinese: 娘子关; traditional Chinese: 娘子關; pinyin: Niángzǐguān) is a town located in north-east of Pingding County, Shanxi, near the location of the Niangzi Pass and the border with Hebei and situated 27 kilometres (17 mi) northeast of the county seat.

The other is that Li Shimin's sister-the Princess Pingyang once led Niangzijun to guard the pass, so later generations called it Niangziguan.

Niangziguan is the key point to Shanxi so there is a special custom called Horse Race (跑马).

On 16 January every year, local people take their horses, asses and mules to gather in Dongzhai Village (董寨村) to circle in a 400-meter-long alley.

People put a lot of ashes on the street to avoid slipping as well as make the atmosphere active.