Taosi (Chinese: 陶寺; pinyin: Táosì) is an archaeological site in Xiangfen County, Shanxi, China.

This was discovered from 1999 to 2001 by the archaeologists from the Institute of Archaeology, Chinese Academy of Social Sciences; they attributed this wall to the Middle Taosi period (4,100 to 4,000 BP).

The settlement is the largest Longshan site discovered in the Linfen basin of the Yellow River, and is possibly a regional center.

It was not the Taosi polities but the less socially complex Central Plains Longshan sites, the scattered, multi-system competing systems that gave rise to early states in this region.

This wall or line of pillars was linked to a central position from which observations could be made by peering through the empty spaces.

This means these slots might share a function similar to the Thirteen Towers of the Chankillo Observatory, having been intentionally constructed for calendrical observation of the sunrise on particular given days, in order to follow the local solar calendar, which would have been crucial for rituals and also for the practice of agriculture at that time.

[7] A painted pole discovered in a tomb at the prehistoric site dating from perhaps 2000 or 2300 BCE is the probably the oldest gnomon known in China.

[14] In Chinese classic documents Yao Dian (Document of Yao) in Shang Shu (Book of Ancient Time), and Wudibenji (Records for the Five Kings) in Shiji (Historic Records), King Yao assigned astronomic officers to observe celestial phenomena, including time and position of sunrise, sunset, and stars in culmination, in order to systematically establish a lunisolar calendar with 366 days a year with leap month.