is the historical legal system based on the philosophies of Confucianism and Chinese Legalism in Feudal Japan. The political system in accord to Ritsuryà  is called "Ritsuryà Â-sei" (). Kyaku () are amendments of Ritsuryà Â, Shiki () are enactments.
Ritsuryà  defines both a and an .
During the late Asuka period (late 6th century â 710) and Nara period (710âÂÂ794), the Imperial Court in Kyoto, trying to replicate China's rigorous political system from the Tang dynasty, created and enforced some collections of Ritsuryà Â. Over the course of centuries, the ritsuryà  state produced more and more information which was carefully archived; however, with the passage of time in the Heian period, ritsuryà  institutions evolved into a political and cultural system without feedback.
In 645, the Taika reforms were the first signs of implementation of the system.
Major re-statements of Ritsuryà  included the following:
In the later half of the seventh century, the was introduced, dividing the regions of Japan into several administrative divisions.
In 715 CE, the was introduced, resulting in the following.
This system was abandoned in 740 CE.
The ritsuryà  system also established a central administrative government, with the emperor at its head. Two departments were set up:
Posts of those public Departments were all divided into four ranks (shità Â): kami (), suke (), jà  () and sakan (). This ubiquitous pattern would be replicated consistently, even amongst members of the court whose functions had little to do with those kinds of powers and responsibilities which are conventionally associated with governing. For example:
A global system of ranking for all public posts ( kan, kanshoku) was introduced with over 30 ranks ( i, ikai), regulating strictly which posts could be accessed by which rank. Ranking was supposed to be mostly merit-based, the children of high-ranking public officials were nonetheless granted a minimal rank. This provision ( on'i no sei) existed in the Tang law, however under the Japanese ritsuryo ranks for which it was applied were higher as well as the ranks obtained by the children.
The highest rank in the system was the first rank ( ichi-i), proceeding downwards to the eighth rank ( hachi-i), held by menials in the court. Below this, an initial rank called so-i () existed, but offered few rights. The top six ranks were considered true aristocracy (è²´ ki), and were subdivided into "senior" ( shà Â) and "junior" ( ju) ranks (e.g. senior third-rank [ shà  san-mi], junior second-rank [ ju ni-i]). Below the third rank, a further subdivision between "upper" ( jà Â) and "lower" ( ge) existed, allowing for ranks such as âÂÂjunior fourth rank lowerâ ( ju shi-i no ge) or âÂÂsenior sixth rank upperâ ( shà  roku-i no jà Â). 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 [ kizoku]) and the menials (sixth-rank and below [ jige]).
Additionally, income in the form of koku (, 1 koku = about 150 kilograms), or bushels of rice from the provinces, increased dramatically as one advanced in rank. The average sixth-rank official might earn 22 koku of rice a year, but the fifth rank might earn 225 koku of rice, while a third rank official could earn as much as 6,957 a year.
Registration of the citizens ( koseki), updated every 6 years, and a yearly tax book ( keichà Â) were established. Based on the keichà Â, a tax system was established called ( So-yà Â-chà Â). Tax was levied on rice crops but also on several local products (e.g. cotton, salt, tissue) sent to the capital.
The system also established local corvée at a provincial level by orders of the kokushi (), a corvée at the Capital (although the corvée at the capital could be replaced by goods sent) and military service.
A criminal system was introduced, with .
It defined that were exempt from amnesty which included the following list of unpardonable crimes:
The code was based on the Ten Abominations of the Tang code, but two crimes related to family lifeâÂÂfamily discord and disruption of the family (through incest, adultery, etc.) âÂÂwere removed.
In accordance with Chinese legal codes, land as well as citizens were to be "public property" (). One of the major pillars of the Ritsuryà  was the introduction of the Handen-Shà «ju () system, similar to the equal-field system in China. The Handen-Shà «ju regulated land ownership. Based on the registration, each citizen over 6 was entitled to a , subject to taxation (approx. 3% of crops). The area of each field was 2 for men (approx. 22 ares total), and two-thirds of this amount for women. (However, the Shinuhi and Kenin castes were only entitled to 1/3 of this area). The field was returned to the country at death. Land belonging to shrines and temples was exempt from taxation. Collection and redistribution of land took place every 6 years.
The population was divided in two castes, Ryà Âmin () (furthermore divided into 4 sub-castes) and Senmin () (divided into 5 sub-castes), the latter being close to slaves. Citizens wore different colors according to their caste.
Several modifications were added over time. In order to promote cultivation, a law allowing the ownership for three generations of newly arable fields was promulgated in 723 (, Sanze-isshin Law) and then without limits in 743 (, Konden Einen Shizai Law). This led to the appearance of large private lands, the first shà Âens.
Strict application of the Handen-Shà «ju system decayed in the 8th and 9th century. In an attempt to maintain the system, the period between each collection/distribution was extended to 12 years under Emperor Kanmu. At the beginning of Heian period, the system was almost not enforced. The last collection/distribution took place between 902 and 903.
The caste system was less and less strictly enforced. Some Ryà Âmin would wed Senmin to avoid taxation, and Senmin/Ryà Âmin children would become Ryà Âmin. At the end of the 9th century / beginning of the 10th, the caste system was practically void of its substance.
Hereditary high-ranks for public posts led to the monopoly of occupation of the most important posts by a limited number of families, in effect a nobility, amongst which the Fujiwara clan, Minamoto clan, Taira clan and the Tachibana clan.