The Longshan culture was the late Neolithic culture of the Central Plains in China, centered on modern Henan and Shandong and dated to 3000-1900 BCE. Some if its defining characteristics were rammed earth walls and foundations, agriculture based on grains (primarily millet) and livestock (especially pigs), burial practices that hint at ancestor worship, occassional human sacrifice, and a particular type of extremely fine pottery. The Longshan culture was made up of a number of large towns with satellite villages, and some of these towns were fortified with defensive walls, indicating a fairly dense population and an ability to mobilize people for construction (erecting walls) or war (making walls worthwhile), but the Longshan towns are generally not regarded as "states." It seems that Longshan society was organized by lineage groups rather than by governments.

It's important to note that the Longshan is an archaeological culture, meaning it was identified by archaeologists after the discovery of similar artifacts across a certain area within certain dates. It is a material culture, defined by physical objects. Since the Longshan culture was not literate, we do not know what language(s) the Longshan people spoke or what kind of self-concept they had. There were also a number of other Neolithic cultures in and around China dating to the same period, and the contacts between these various cultures are still not fully understood.

That being said, the Longshan culture is considered ancestral to the literate, Bronze Age Shang culture in the material sense because of the similarities in agriculture, architecture and apparent religious practice as well as their geographical overlap.