Yamashina Nishinoyama Kofun Excavated Artifacts: National Treasure of Early Heian Japan

Hidden within the collections of the Kyoto University Museum lies one of Japan's most captivating archaeological treasures — a group of exquisite artifacts excavated from the Nishinoyama Tomb in Kyoto's Yamashina district. Designated as a National Treasure in 1953, these grave goods include a gold-decorated sword, a magnificent bronze mirror adorned with gold and silver phoenix motifs, iron arrowheads, and a ceramic ink-stone, among other items. What makes this collection especially fascinating is its connection to one of Japan's most legendary historical figures: Sakanoue no Tamuramaro, the great Sei-i Taishōgun (Barbarian-Subduing Generalissimo) of the early Heian period.

The Discovery: An Accidental Find in a Bamboo Grove

In 1919, local residents in the Nishinoyama area of Yamashina were performing routine soil work in a bamboo grove — a seasonal task essential for cultivating bamboo shoots — when they unexpectedly uncovered a wooden coffin encased in charcoal. Kyoto Imperial University (now Kyoto University) promptly dispatched the archaeologist Umehara Sueji to conduct a formal excavation, which revealed a remarkable assemblage of burial goods within a charcoal-sealed wooden coffin (mokutan-kaku mokkan-bo).

The artifacts recovered from the tomb paint a vivid picture of the wealth and status of the person buried there. The collection includes a gold-mounted great sword (kinsō tachi), a bronze mirror decorated with gold and silver twin-phoenix designs using the heidatsu lacquer technique, fragments of a stone-studded belt befitting a high-ranking court official, a small knife (kogatana), iron arrowheads, two iron plates believed to be fragments of a grave epitaph, a tile-shaped ink-stone, a ceramic water dropper, and iron nails from the coffin itself.

Why These Artifacts Are Designated a National Treasure

The artifacts from Nishinoyama Tomb were first designated as a National Treasure under the old National Treasure Preservation Law in 1936, and then re-designated under the new Cultural Properties Protection Law in 1953. Several factors contribute to their exceptional cultural significance.

First, the gold-mounted sword is an extraordinary example of early Heian metalwork. Its blade fittings are adorned with pure gold — a level of opulence comparable to items preserved in the Shōsōin Repository in Nara. The craftsmanship and materials used reflect the highest ranks of aristocratic society in early ninth-century Japan.

Second, the gold-and-silver heidatsu twin-phoenix mirror (kingin heidatsu sōhō-mon kyō) is a masterpiece of decorative metalwork. The heidatsu technique involves cutting thin sheets of gold and silver into decorative patterns and affixing them to the lacquered surface of a bronze mirror — a technique that flourished during the Nara and early Heian periods under strong Tang Chinese influence.

Third, the belt ornament stones (sekitai) recovered from the tomb are consistent with the white jade stones permitted only for court nobles of the third rank or above, or fourth-rank officials serving as imperial advisors (sangi). This detail places the tomb occupant firmly among the highest echelons of Heian aristocratic society.

Finally, the tile-shaped ink-stone dates to the late Nagaoka-kyō or early Heian period, and the presence of both military items (sword, arrowheads) and scholarly implements (ink-stone, water dropper) suggests a person who combined martial prowess with administrative authority — a rare combination in Japan's court hierarchy.

The Tamuramaro Connection: Tomb of a Legendary General?

For decades after its discovery, the tomb was attributed to the Nakatomi clan, whose ancestral lands lay in the Yamashina area. However, in the 1970s, local historian Torii Haruo proposed a revolutionary theory: that the Nishinoyama Tomb was actually the burial site of Sakanoue no Tamuramaro (758–811), the celebrated Sei-i Taishōgun who pacified the Emishi peoples of northern Japan and is traditionally credited with founding Kiyomizu-dera Temple.

Historical records state that upon Tamuramaro's death in 811, Emperor Saga ordered that the general be buried in full armor, facing east toward the capital, so that his spirit could continue to protect Heian-kyō (modern Kyoto). According to these accounts, whenever the nation faced danger, the tomb would rumble like thunder — a phenomenon known as "Shōgunzuka meidō" (the rumbling of the General's Tomb).

In 2007, Professor Yoshikawa Shinji of Kyoto University's Graduate School of Letters strengthened this theory by cross-referencing administrative documents with historical maps, identifying the Nishinoyama site as consistent with the recorded location of Tamuramaro's burial. The tomb's position at the eastern entrance to the Kyoto Basin, facing toward the capital, aligns perfectly with the historical descriptions. However, some scholars remain cautious, noting the absence of armor among the excavated artifacts, and alternative theories have suggested the tomb might even be associated with Emperor Kanmu (737–806).

Highlights of the Collection

The National Treasure designation covers the entire assemblage as a single group, reflecting the importance of these items as a coherent burial context. Here are the key pieces that make this collection extraordinary.

The gold-mounted great sword (kinsō tachi zanketsu) is the centerpiece of the collection. Although only fragments survive, the pure gold fittings demonstrate exceptional craftsmanship rivaling treasures in the Shōsōin Repository. The sword's four accompanying belt-hanging hardware pieces (taishu kawa kazari kanagu) further attest to the owner's elite status.

The gold-and-silver heidatsu twin-phoenix mirror showcases Tang-era decorative techniques adapted for Japanese aristocratic use. The mirror was found with fragments of its lacquered mirror case (kyōren), indicating it was carefully stored as a prized personal possession.

The two iron plates, though heavily corroded, are believed to have been a grave epitaph (boshi). Despite X-ray analysis, no legible inscriptions have been confirmed, leaving the identity of the tomb occupant an enduring mystery that continues to fuel scholarly debate.

Visiting the Kyoto University Museum

The excavated artifacts from Nishinoyama Tomb are housed at the Kyoto University Museum (Kyoto Daigaku Sōgō Hakubutsukan), located on the university's main Yoshida Campus in Kyoto's Sakyō Ward. As one of Japan's largest university museums, the facility holds over 2.6 million items spanning cultural history, natural history, and the history of technology.

Please note that the Nishinoyama artifacts are not always on permanent display due to conservation requirements. They may be exhibited during special exhibitions or on rotating schedules. It is advisable to contact the museum or check their website before visiting if you specifically wish to see these National Treasure items.

The museum itself is well worth a visit even beyond these specific artifacts. The cultural history galleries feature archaeological materials ranging from ancient stone coffins to historical maps and documents, providing rich context for understanding the Nishinoyama finds within the broader story of Japanese civilization.

Surrounding Area and Related Sites

A visit to the Kyoto University Museum can be combined with exploration of several related sites and nearby attractions that enrich the experience.

The approximate location of the original Nishinoyama Tomb is in Yamashina Ward, along the Nameishi Highway (Nameishi Kaidō). A stone marker reading "Kono fukin Nishinoyama Kobo" (This vicinity: Nishinoyama Ancient Tomb) stands near the site, though the exact tomb location is enclosed behind fencing and overgrown with bamboo. The area offers a contemplative atmosphere that evokes the tomb's long history.

The officially designated Sakanoue no Tamuramaro Tomb (also called Shōgunzuka) in Yamashina Ward's Kanshuji area was established in 1895 to mark the 1,100th anniversary of the transfer of the capital to Heian-kyō. Set in the peaceful Tamura-no-Mori Park, this memorial site offers visitors a chance to pay respects to the legendary general, though scholars now believe the actual burial was at the Nishinoyama site.

Kiyomizu-dera Temple, one of Kyoto's most famous landmarks, is traditionally attributed to Sakanoue no Tamuramaro. A visit here allows you to appreciate the legacy of the man who may lie buried in the Nishinoyama Tomb. Within the temple grounds, a monument dedicated to Aterui and More — the Emishi leaders whom Tamuramaro fought against and later tried to save — adds further historical depth.

The Kyoto National Museum, located a short distance from Kiyomizu-dera, occasionally features Nishinoyama artifacts in its special exhibitions. Its outstanding collection of Japanese art and archaeology provides additional context for understanding early Heian material culture.