In his column What exactly is the Manusmriti?, Devdutt Pattanaik says the Manu mentions China. Which verse(s) is he referring to?
Manusmriti was composed roughly around 200 CE (Common Era). We know this because it refers to Saka (North West tribes) and Cheen (China) who established contact with India around this time.
The word "China", referring to a particular tribe, is found in Manu Smriti 10.44:
10.43. But in consequence of the omission of the sacred rites, and of their not consulting Brahmanas, the following tribes of Kshatriyas have gradually sunk in this world to the condition of Sudras
10.44. (Viz.) the Paundrakas, the Chodas, the Dravidas, the Kambogas, the Yavanas, the Sakas, the Paradas, the Pahlavas, the Chinas, the Kiratas, and the Daradas.
10.45. All those tribes in this world, which are excluded from (the community of) those born from the mouth, the arms, the thighs, and the feet (of Brahman), are called Dasyus, whether they speak the language of the Mlecchas (barbarians) or that of the Aryans
The relevant verse in Sanskrit is:
PoundrakAsha chauda drAvidAh kambojA yavanAh shakAh |
PAradA pahlavAsh chinAh kirAtA daradA khashA ||
So, according to Manu Smriti, all those tribes, including the China tribe, were originally Kshatriyas, but due to non-performance purificatory and sacred rites, they became VrAtyas and degraded themselves to the status of the Sudras.
