Nakatsukasa-sho (Ministry of Central Affairs, "中務省" in the Chinese characters) was a government-regulated organization under the Ritsuryo system (a system of centralized government based on the ritsuryo codes).
It was also called by a Japanese name, 'Naka no matsurigoto no tukasa.'
The Chinese character '中' of "中務省" has a meaning of the Imperial Court.
Nakatsukasa-sho was regarded as the most important ministry among the eight central ministries, because it administered all duties related to the Imperial Court, such as assisting the Emperor, proclaiming the imperial edict, conferring the court rank. There is a theory that Nakatsukasa-sho along with Kunai-sho (Ministry of the Sovereign's Household) was ranked higher than other six ministries before the establishment of Taiho Ritsuryo (Taiho Code).
Therefore, the Nakatsukasa-Kyo (corresponding to Shoshiinojo [Senior Fourth Rank Upper Grade]), the Secretary of Nakatsukasa-sho, was conventionally chosen from the Imperial Princes with a rank equivalent to or higher than Shihon (the fourth rank of Imperial Princes' rank) exclusively in and after the Heian period. Even if the post became vacant, it remained unfilled until an Imperial Prince suitable for the post appeared.
This ministry had to cover extensive duties, because it managed the general clerical works related to the Imperial Court from enforcement of the imperial edict to the personnel affairs concerning court ladies in Kokyu (empress's residence). Therefore, in addition to Shitokan (four classifications of bureaucrats' ranks, the official court ranks conferred to the Shitokan of Nakatsukasa-sho were higher than Shitokan in other ministries) consisting of Suke, Jo and Sakan, the following posts were counted among Honkan (government posts): Jiju (chamberlain); officials attending the Emperor, Udoneri (Ministerial equerry); officials taking charge of the Imperial Court defense and miscellaneous jobs and guarding an imperial visit, Naiki and others; officials engaged in drafting the two types of imperial edict (one was written in the classical Chinese and the other was in the Japanese syllabary) and the court rank diploma, Kenmotsu and others; officials engaged in accounts of Okura-sho (Ministry of the Treasury), Kura-ryo (Bureau of Palace Storehouses), etc., Shurei and Tenyaku; officials managing Ekirei (bells set in stations used for supplying horses), Denfu (certification for lending horses), etc. Meanwhile, the Udoneri guarding the Emperor and the Jiju, attendants of the Emperor, was obliged to wear a sword.
Government offices under high-ranked offices in Nakatsukasa-sho were categorized into one-shiki (the Ritsuryo system), six-ryo (the Ritsuryo system) and three-shi under the Ritsuryo system. However, this system was later streamlined to decrease the number of categories to one-shiki and six-ryo.
The quota of the posts equivalent to or lower than Taifu (Vice-Minister)
The quota of the posts in this ministry equivalent to or lower than Taifu was as follows.
Taifu (corresponding to Shogoinojo [Senior Fifth Rank, Upper Grade]) … one person
Shofu (Junior Assistant Minister, corresponding to Jugoinojo [Junior Fifth Rank, Upper Grade]) … one person
Taijo (Senior Secretary, corresponding to Shorokuinojo [Senior Sixth Rank, Upper Grade]) … one person
Shojo (Junior Secretary, corresponding to Jurokuinojo [Junior Sixth Rank, Upper Grade]) … two people
Daisakan (Senior Alternate Adjudicator, corresponding to Shoshichiinojo [Senior Seventh Rank, Upper Grade]) … one person
Shosakan (Junior Alternate Adjudicator, corresponding to Shohachiinojo [Senior Eighth Rank, Upper Grade]) … three people
Note: The supernumerary post called Gonkan was later attached to Taifu and Shofu.
Shisho (officials doing miscellaneous duties about documents)
Shojo (low-ranked officials to convey petitions)
Shibu (low-ranked bureaucrats)
Jiju (corresponding to Jugoinoge [Junior Fifth Rank, Lower Grade]) … eight people when Taiho Code was enacted, later increased to 20 people
Udoneri … 90 people when Taiho Code was enacted, later the number fluctuated.
Dainaiki (high-ranked Naiki, corresponding to Shorokuinojo) … two people
Chunaiki (middle-ranked Naiki) … two people when Taiho Code was enacted, later abolished
Shonaiki (low-ranked Naiki, corresponding to Shoshichiinojo) … two people
Daikenmotsu (high-ranked Kenmotsu, corresponding to Jugoinoge) … one person
Chukenmotsu … four people when Taiho Code was enacted, later abolished
Shokenmotsu (low-ranked Kenmotsu, corresponding to Shoshichiinoge [Senior Seventh Rank, Lower Grade]) … four people.
Kenmotsu-sakan (assistant of clerical work of Kenmotsu, corresponding to Jushichiinoge [Junior Seventh Rank, Lower Grade]) … newly established
Daishurei (high-ranked Shurei, corresponding to Shoshichiinoge) … two people
Shoshurei (low-ranked Shurei, corresponding to Shohachiinojo) … two people
Daitenyaku (high-ranked Tenyaku, corresponding to Jushichiinoge) … two people
Shotenyaku (low-ranked Tenyaku, corresponding to Juhachiinojo [Junior Eighth Rank, Upper Grade])… two people
Government offices under high-ranked offices in Nakatsukasa-sho
Chugushiki (Office of the Consort's Household)
Otoneri-ryo (Bureau of Imperial attendants, there were two bureaus under the Ritsuryo system, Hidari (left) no Otoneriryo and Migi (right) no Otoneriryo])
Zusho-ryo (Bureau taking charge of preserving drawings and books)
Nuidono-ryo (Bureau taking charge of sewing Wardrobe and managing court ladies)
Onmyo-ryo (Bureau taking charge of divination)
Takumi-ryo (Bureau of skilled artisans) - Ryoge no kan (a post outside the original Ritsuryo code created by Imperial edicts)
Gako-shi (Bureau taking charge of painting) - merged into Takumi-ryo in 808
Naiyaku-shi (private doctors for the Emperor) -merged into Tenyaku-ryo (Bureau of medicine) of Kunai-sho in 896
Nairai-shi (Bureau for cracking down on illegalities) -merged into Danjodai (Board of Censors) in 808