Ruiju Kokushi Volume 25: An Ancient Encyclopedia of Japanese Imperial History

Tucked away within the carefully climate-controlled archives of Tohoku University in Sendai lies one of Japan's most remarkable literary treasures: the Ruiju Kokushi Volume 25 (類聚国史巻第廿五). Designated as a National Treasure of Japan, this handscroll manuscript represents a direct link to the intellectual world of ninth-century Japan, when the celebrated scholar-statesman Sugawara no Michizane compiled one of the most ambitious historical projects in Japanese literary history.

The Ruiju Kokushi, or "Classified National History," was completed in 892 under the command of Emperor Uda. Its purpose was both practical and scholarly: to reorganize the vast content of Japan's Six National Histories (Rikkokushi) into thematic categories, making it far easier for court officials to search for precedents and historical references. Volume 25, preserved at Tohoku University, belongs to the "Emperor" (Teiō) section and offers invaluable insights into the lives and reigns of ancient Japanese sovereigns.

What Is the Ruiju Kokushi?

The Ruiju Kokushi is a monumental work of historical compilation that draws upon the Six National Histories of Japan—a series of official chronicles spanning from the mythological age to the late ninth century. These six histories are the Nihon Shoki, Shoku Nihongi, Nihon Kōki, Shoku Nihon Kōki, Nihon Montoku Tennō Jitsuroku, and Nihon Sandai Jitsuroku.

Rather than presenting events in chronological order, Sugawara no Michizane reorganized the content into eighteen thematic categories, including deities, emperors, consorts, annual events, music, government administration, criminal law, Buddhist teachings, and natural disasters. The original work comprised approximately 200 volumes of text, two catalogues, and three genealogical charts. However, the devastating Ōnin War (1467–1477) and other disasters caused the loss of the majority of the collection, and only about 62 volumes survive today.

One of the most notable features of the Ruiju Kokushi is its strict adherence to the original texts. Michizane deliberately avoided making any alterations to the source material, preserving the exact wording of the Six National Histories. This editorial principle makes the work invaluable for modern scholars, particularly for reconstructing portions of the Nihon Kōki, much of which has been lost.

Volume 25: The Emperor Section, Part Five

The volume held at Tohoku University is Volume 25, which falls within the "Emperor" (Teiō-bu) category—specifically the fifth part of this section. While the first four parts of the Emperor section are believed to have covered the births, enthronements, deaths, and abdications of successive emperors, Part Five focuses on two distinct topics.

The first half, titled "Daijō Tennō" (Retired Emperors), contains records concerning eleven retired emperors beginning with Empress Jitō, documenting primarily their abdications and deaths. The second half, titled "Tsuigō Tennō" (Posthumously Titled Emperors), records four individuals—beginning with Prince Kusakabe (known as Okanomiya no Sumeramikoto)—who were granted the title of emperor after their deaths. These records provide crucial insights into the political dynamics and ceremonial practices of ancient Japan's imperial court.

Why Was It Designated a National Treasure?

Volume 25 of the Ruiju Kokushi was designated as a National Treasure on November 22, 1952. Several factors contributed to this prestigious recognition.

First, the manuscript is a late Heian period copy, making it one of the oldest surviving manuscripts of this text. Its age and condition provide scholars with a window into the scribal practices and materials of medieval Japan. The handscroll measures approximately 27.9 cm in height and 159.4 cm in length, and experts have determined that it was written by several different scribes rather than a single copyist, adding to its historical interest.

Second, the volume is of extraordinary scholarly value. As one of only about 62 surviving volumes out of an original 200, each extant copy carries immense weight for understanding the lost portions of Japan's national histories. The text is particularly important for reconstructing the Nihon Kōki, large sections of which are no longer available in their original form.

Third, the manuscript's provenance is remarkable. It was originally held by the Mibu family (Mibu Kanmu-ke), a lineage of court officials who served as the chief administrators (Kanmu) of the Grand Council of State (Daijōkan). The Mibu family's role in managing official court documents made them natural custodians of such historical texts. The manuscript later passed through various hands before being acquired by Kanō Kōkichi (1865–1942), a distinguished scholar who served as principal of the First Higher School and dean of the Faculty of Letters at Kyoto Imperial University. His vast collection was ultimately transferred to Tohoku University, where it remains today as part of the renowned Kanō Collection.

Sugawara no Michizane: The Scholar Behind the Masterwork

Sugawara no Michizane (845–903) is one of the most revered figures in Japanese cultural history. A brilliant poet, scholar, and statesman of the early Heian period, he rose to the rank of Minister of the Right before being unjustly exiled to Dazaifu in Kyushu due to political intrigue. After his death, a series of calamities befell his political enemies, and he was posthumously deified as Tenjin, the god of learning and literature. Today, Tenjin shrines across Japan are visited by millions of students praying for academic success.

The compilation of the Ruiju Kokushi was one of Michizane's greatest scholarly achievements. Commissioned by Emperor Uda, the project reflected the Chinese tradition of "leishu" (classified encyclopedias), which organized existing texts by subject matter for easy reference. Michizane's meticulous approach—preserving original texts without modification—ensured that his compilation would remain an indispensable resource for historians for over a millennium.

The Kanō Collection and Tohoku University

The story of how Volume 25 came to reside in Sendai is itself a fascinating chapter in the history of Japanese academic collections. Kanō Kōkichi, the scholar who assembled the collection, was a close friend of Sawyanagi Masatarō, the first president of Tohoku Imperial University (now Tohoku University). Through Sawyanagi's efforts, Kanō agreed to transfer his extensive library to the university on the condition that it be kept together permanently.

The Kanō Collection, comprising approximately 108,000 volumes, is sometimes called "an encyclopedia of classical literature" or "a treasury of Edo-period learning." It contains an extraordinary range of materials spanning Japanese and Chinese classics across numerous disciplines. The two National Treasures within this collection—Volume 25 of the Ruiju Kokushi and a copy of the Chinese historical text Shiji (Records of the Grand Historian) dating to 1073—stand as its most prestigious items.

Today, Tohoku University maintains these treasures under strict environmental controls, ensuring their preservation for future generations. The university's digital archive initiative has also made high-resolution images of selected items available to researchers worldwide, broadening access to these irreplaceable documents.

Visiting Tohoku University and Sendai

While the original manuscript of the Ruiju Kokushi is kept in secure storage and is not on permanent public display due to its extreme fragility, Tohoku University periodically features its National Treasures in special exhibitions. Visitors interested in seeing the manuscript should check the university library's website or contact them in advance for exhibition schedules.

The Katahira Campus, where the manuscript is housed, is itself a rewarding destination. Located about one kilometer west of JR Sendai Station, the campus retains many historic buildings from the Taishō and early Shōwa eras, including the former lecture hall where the celebrated Chinese writer Lu Xun once studied. The campus is also designated as one of Sendai's "100 Green Sites," with beautiful metasequoia-lined avenues and cherry blossom paths.

Sendai, known as the "City of Trees" and the largest city in the Tohoku region, offers a wealth of attractions for visitors. The ruins of Sendai Castle (Aoba Castle), built by the legendary feudal lord Date Masamune, provide panoramic views of the city. The nearby Ōsaki Hachiman Shrine, another National Treasure, showcases stunning Momoyama-period architecture. For those seeking natural beauty, the scenic bay of Matsushima—one of Japan's three most celebrated views—is just a short train ride away.

Practical Information for International Visitors

Sendai is easily accessible from Tokyo via the Tōhoku Shinkansen, with a journey time of approximately 90 minutes. The Katahira Campus is within walking distance from Sendai Station (approximately 15 minutes on foot) or can be reached by the Sendai City Subway to Ōmachi-Nishi-Kōen Station. International visitors will find that Sendai has a welcoming atmosphere, with English signage at major stations and tourist information centers available in multiple languages.

The Sendai City Museum, located near the castle ruins, features exhibits on local history and the Date clan, and occasionally displays items from Tohoku University's collections. For those interested in Japanese calligraphy and manuscript traditions, a visit to the university's special exhibitions can be combined with exploring the broader historical and cultural sites of this vibrant city.