Dai Nihon Shiryo: Filling the Gaps in the Past

“The more I study history the more I realize how little mankind has changed. There are no new scripts, just different actors.” Richard Paul Evans

"Dai Nihon Shiryo" is an extensive collection of historical documents on Japanese history, initiated in 1901 (Meiji 34) and continuing to this day. This project was started after recognizing a significant gap in the national historical records post the Six Kingdoms History, which ended with the "Nihon Sandai Jiroku." To address this gap, the compilation aimed to document the history from the reign of Emperor Uda, who ascended the throne in 887 during the Heian period, extending through to the Edo period. It organizes major historical events in chronological order and includes a list of historical sources that serve as references for these events.

In 1895 (Meiji 28), the College of Letters at the Imperial University established the Historiography Department, now known as the Historiographical Institute of the University of Tokyo, marking the beginning of an ambitious project to compile historical books. Originally intended to write an official general history, the project shifted focus towards assembling a collection of historical materials, inspired by the Meiji government's initiative to revise historical narratives.

The compilation's editorial approach was influenced by the historical sources gathered by the Wagakou Kodansho, an Edo period institution founded by Koichi Hanawa. This led to the creation of "Shiryo," a comprehensive collection documenting the period following Emperor Uda's reign up to the year 1024 (the first year of Emperor Goichijo's reign). The project meticulously covered the era from 887 (Ninna 3) to 1867 (Keio 3) across 16 volumes, resulting in the 'Historical Materials Manuscript,' which contains approximately 5,600 drafts.

Publication of "Dainippon Shiryo" commenced in 1901 (Meiji 34), starting with the sixth volume, which covers the Nanbokucho period, and notably includes the "Taiheiki" among its sources. The twelfth and fourth volumes, covering the Edo and Kamakura periods respectively, followed shortly thereafter.

The publication was halted from 1945 to 1951 due to World War II's impact on Japan, but resumed in 1952 under the direction of Taro Sakamoto. Over the past century, this monumental effort has consistently resulted in the publication of several volumes per year, reaching a total of 422 books by January 2022.

February 28th, 2024 marks the 123rd anniversary of the publication of the first volume, about the "Nanbokucho-period" or the North and South court period, when there were two imperial courts, one established by Ashikaga Takauji, Shogun, in the name of Emperor Kogon, while Emperor Go-Daigo established a second court in the city of Yoshino in Nara prefecture, and attempted to restore the authority of the throne under his line. Spoiler alert: North wins. But the controversy continues. The generally accepted belief is that Go-Daigo was the legitimate line of succession, and the figureheads installed by Ashikaga Takauji are merely pretenders to the throne. In 1946, a man named Kumazawa Hiromichi presented a family register (koseki) which traced his lineage back to Emperor Go-Daigo. The claim at the time was that then Emperor Showa (Hirohito) was descended entirely from Northern Court pretenders, and thus was illegitimate. Emperor Showa was the grandfather of the current Emperor Reiwa (Naruhito). Kumazawa's claims were never confirmed nor refuted. Prior to and during World War 2, claiming to be the rightful emperor was considered lese majeste and was punishable by law, but during the post-war occupation, Kumazawa was not prosecuted. The relevance of an official historical document like the Dai Nihon Shiryo to debates like this is immediately obvious.

The last four volumes of the Dai Nihon Shiryo are, as of writing, unpublished. They cover the Edo period from 1651 to 1867. Additionally, Volume 12 is incomplete, terminating in May of 1623. As more historically valid documents are identified and cataloged, new years are added to the historical record, and sometimes existing years are expanded based on the discovery of new information. It is an ever-developing record of the past, changing and expanding into the future.