Honcho Gatsuryo (本朝月令)
Honcho Gatsuryo (or Honcho Getsurei) is the oldest remaining kuji-sho (a document about governmental operations and ceremonies) where, concerning annual events in the middle era of the Heian period, their origins, histories and contents are described. The author was KOREMUNE no Kinkata, Myobo hakase (a teacher of the law in the Ritsuryo system). His father was KOREMUNE no Naomoto who wrote "Ryonoshuge" (Commentaries on the civil statutes), and KOREMUNE no Masasuke who wrote "Seiji Yoryaku" (examples of the politics in the Heian period) was his grandson. Of the four volumes, only volume two for April - June remains today.
This document was not described based on the author's own opinions, but was written using the reference-based method in which explanations were made by citing laws of codes and ethics (conduct), descriptions in national histories and Japanese/Chinese dictionaries. Therefore, descriptions in ancient books or rare books that do not remain now can be found in this book. Furthermore, the citation from original documents was made relatively correctly. Therefore, this document is useful not only for research on Yusoku kojitsu (court and samurai rules of ceremony and etiquette) but also for the research for restoring descriptions that have been lost. In addition, the policy employed for compiling this document also affected that of "Seiji Yoryaku." For example, this document was used, as it was, in the annual event part of "Seiji Yoryaku" and citations about national history in the augmented portion was made from "Ruiju Kokushi" (a national history compiled by SUGAWARA no Michizane). Therefore, in the annual event part of "Seiji Yoryaku," citations concerning national history were made from Rikkokushi (six official national histories) and from "Ruiju Kokushi."
When the compilation of this document was completed is known from the following two items: (1) the description of national mourning events on the same day of June, in "Honcho Gatsuryo," and (2) a comparison of the documents referred to in "Honcho Gatsuryo" and those in "Seiji Yoryaku."
First, concerning (1), the description includes 'The title of Empress was awarded after her death; her posthumous name was FUJIWARA no Inshi; the mother (妣) of the former Emperor.'
FUJIWARA no Inshi was a nyogo (a consort) of Emperor Uda and the mother of Emperor Daigo. Because the character '妣' indicates a mother, the former emperor was Emperor Daigo. Therefore, the emperor who could call Emperor Daigo as the former emperor was the emperor who succeeded Emperor Daigo, or Emperor Suzaku.
Concerning (2), compared with the documents referred to in "Seiji Yoryaku," one of those not referred to in this document is "Seiryoki." Because "Seiryoki" was complete in 946, this document must have been complete in 946 or before.
From those described above, it can be considered that this document was complete in the era of Emperor Suzaku, but there are also other theories insisting that it was complete in the era of 901 - 923 or in the era of Emperor Murakami.
There are the following manuscripts of this document: One is the book that is said to have been copied in the Kamakura period and was formerly kept in the Kujo family (now kept in the Imperial Household Archives), and another is the book that was partially copied in around 1334 -1336 and was formerly kept in the Kanazawa Library (now kept in Sonkeikaku-bunko library). There are manuscripts copied in the early-modern times as well, and they are based on the book formerly kept in the Kujo family.