Shinsei (Law reconstitution) (新制)

Shinsei ('kugeshinsei') means a written code established based upon imperial order by Tenno (the Emperor) and Daijo Tenno (the Retired Emperor) from the mid Heian period to the period of the Northern and Southern Courts (Japan). It is also called seifu, which means 'Shinsei enforced by kanpu' (official documents issued by Daijokan, Great Council of State). The same sorts of legal codes were established by Kamakura bakufu (Japanese feudal government headed by a shogun) and temples.
The former was called 'Buke shinsei' or 'Kanto shinsei' and the latter was called 'Jisha shinsei' or 'Jihen shinsei.'
Both of these are sometimes included in shisei in a broad sense.

Summary

Originally, shinsei was a word meaning a new ban. In later times, however, it changed its meaning to a reform (shin) in the right direction and an edict (sei) for that purpose. It was promulgated in the form of kanpu (Daijokanpu, which means official documents issued by Daijokan, Grand Council of State) through a council called Jin no sadame (ancient cabinet council) held by Daijokan (Grand Council of State) at the behest of the Emperor or the Retired Emperor in power (Chiten no kimi) aiming at the restoration of order of the Ritsuryo system (a system of centralized government based on the ritsuryo code). There were examples in which it was issued as senshi (an imperial decree), Kan senji (an edict from Daijokan which had the status of a binding official document), or Inzen (a decree from the retired Emperor). In some cases, it was in the form of a single article, but it normally consisted of several articles or several tens of articles (the most numerous articles were forty-two in Kangi shinsei, which was a new law issued in the Kangi period).
It was named after the number of articles contained, such as 'XX articles of shinsei,' but in later ages, it was called based on era name in which it was issued, such as 'Shinsei of XX' or 'Code of the year XX.'
Moreover, each article consisted of kotogaki (a part of books where the main idea of the book is summarized) and the text. The kotogaki contained the summary and aim of the regulation, and text provided concrete descriptions of the regulations.

The kanpu called Six articles of shinsei promulgated in 947 by Emperor Murakami is regarded as the oldest kanpu. It was issued in the midst of the reformation called Tenryaku no chi (glorious Tenryaku rule) for the purpose of the regulation and the prohibition on extravagant magnificence or variance of clothing among lower-ranking government officials in order to strictly maintain the order of the social status. In 999, Eleven articles of the first year of the Choho era was issued under the system of Emperor Ichijo and FUJIWARA no Michinaga and it became the fixed form of shinsei afterward. The pivotal subjects of shinsei at the time could be broadly divided into two main categories, Shashikinshirei (luxury prohibiting law) and manor regulation acts. In many cases, it aimed especially at tightening discipline of lower-ranking government officials and Buddhist monks including armed priests.

It was not until the enactment of Hogen shinsei (a new law issued in the Hogen period) in September eighteen in the first year of Hogen era by the lunar calendar (November 2, 1156 by the solar calendar) that the nature of shinsei drastically changed. This shinsei not only marked the beginning of a new era ushered in by the enthronement of Emperor Goshirakawa but also aimed at the restoration of centripetal force of the Imperial court by exercising a benevolent rule over the society and allaying the disturbance caused by the Hogen War, which had occurred immediately after the aforementioned event. After that, new shinsei aimed at the display of benevolent rule and royalty was frequently issued on the occasions of change of emperors, disaster, and war, etc. Among others, Kenkyu shinsei (new law issued in the Kenkyu period) in 1191, Kangi shinsei (new law issued in the Kangi period) in 1231 and Bunei shinsei (new law issued in the Bunei period) in 1273 were specially called Sandai seifu (the three major seifu).

Upon issuance of each shinsei, it was directly notified by an envoy who was accredited to the Kamakura bakufu and dominant temples and shrines. The first Buke shinsei (a code of new law issued by the Kamakura bakufu) was issued by the Kamakura bakufu in 1225 to coincide and comply with Karoku shinsei (new law issued in the Karoku period) issued by the Imperial court. Kocho shinsei (new law issued in the Kocho period) of 1261 was the first Buke shinsei issued solely by the bakufu. It was issued by main leadership of Imperial Prince Munetaka, who was a seii taishogun (the great general who subdues the barbarians). Furthermore, Koan shinsei (new law issued in the Koan period), which was the Buke shinsei led by Yasumori ADACHI, was promulgated in 1284. It galvanized the Imperial court to enact its shinsei and led to the movement of political reform, which is called koan-tokusei (political reforms in the Koan era), carried out by the cooperation between the bakufu and the Imperial court. As a result, in the bakufu, the reconstruction of the relationship between shogun and gokenin (an immediate vassal of the shogunate in the Kamakura and Muromachi through Edo periods) was carried out. In the Imperial court, the execution of Shinryo-kogyo (performances of shinto rituals) and the establishment of a litigation system were realized under the Retired Emperor Kameyama.

However, social problems that were becoming more serious disabled the effect of the series of shinsei and brought about its decline.
For example, FUJIWARA no Yorisuke and FUJIWARA no Sadaie criticized the establishment of Kangi shinsei, pointing out the loss of authority of shinsei caused by its excessive issue and the outbreak of political disturbances over its enforcement. (According to the section of March twenty-nine of the 3rd year of Kangi era in "Minkeiki "(the journal by Tsunemitsu HIROHASHI) and the section of April 19 of second year of Kangi era in "Meigetsuki" - Chronicle of the Bright Moon)
The shinsei of 1297 became the last buke shinsei enacted by the Kamakura bakufu. Likewise, in the Imperial court, the shinsei of 1346 issued by the Emperor Komyo of the Northern Court (Japan) became the last kuge shinsei.