Evidence supporting the introduction and evolution of the frame chair is less clear than the folding chair. A key question is whether the chair evolved from the stool or whether the chair came from outside China and was adopted.
Low stools were known from very early times but it is not known if they were used as a seat or as a step on to a structure called a kang. The kang is a hollow platform that is large enough for several people to sleep on and is heated from underneath either by direct fuel or by running a flue from a nearby stove. It is a common structure in the home in northern China where the winters are bitterly cold.
Stools and chairs were known to have been used in other countries long before they arrived in China. For example, 2nd century BC stone carvings show they were used in India. While there is no written evidence it is quite possible that merchants and monks travelling the trade routes might have brought examples in to China.
Another possibility is that chairs may have come in with the introduction of Buddhism in about the 3rd century AD. Some wall paintings from the period do show a person seated, however