During the late Asuka period (late 6th century – 710) and Nara period (710–794), the Imperial Court in Kyoto, trying to replicate China's rigorous political system from the Tang dynasty, created and enforced some collections of Ritsuryō.

[2] Major re-statements of Ritsuryō included the following:[3] In the later half of the seventh century, the Kokugunri system (国郡里制, kokugunri-sei) was introduced, dividing the regions of Japan into several administrative divisions.

The ritsuryō system also established a central administrative government, with the emperor at its head.

[8] The top six ranks were considered true aristocracy (貴 ki), and were subdivided into "senior" (正 shō)[7] and "junior" (従 ju)[7] ranks (e.g. senior third-rank [正三位 shō san-mi], junior second-rank [従二位 ju ni-i]).

Promotion in ranks was often a very gradual, bureaucratic process, and in the early days of the Codes, one could not advance beyond sixth rank except by rare exception, thus causing a natural cut-off point between the aristocrats (fifth-rank and above [貴族 kizoku]) and the menials (sixth-rank and below [地下 jige]).

Based on the keichō, a tax system was established called (租庸調 So-yō-chō).

Tax was levied on rice crops but also on several local products (e.g. cotton, salt, tissue) sent to the capital.

In accordance with Chinese legal codes, land as well as citizens were to be "public property" (公地公民).

Based on the registration, each citizen over 6 was entitled to a "distributed field" (口分田, kubunden), subject to taxation (approx.

At the end of the 9th century / beginning of the 10th, the caste system was practically void of its substance.