Otokuni Tomb Group (Tenno No Mori Tomb / Shiba Tomb / Terato

Otokuni Kofun Group: Thirteen Burial Mounds Tracing 400 Years of Power in Western Kyoto

Spread across the rolling hills and valleys west of Kyoto, the Otokuni Kofun Group (乙訓古墳群) is a remarkable cluster of thirteen ancient burial mounds that together tell the story of more than four centuries of regional leadership during Japan's Kofun period (3rd to 7th century CE). Designated a National Historic Site of Japan in 2016 and expanded in 2018, this collection spans the city of Kyoto, Mukō, Nagaokakyō, and the town of Ōyamazaki, offering a rare opportunity to walk through the political and cultural evolution of an entire region in chronological order.

What makes the Otokuni Kofun Group truly exceptional is the unbroken sequence of chieftain tombs from the very dawn of mound-building in Japan to its twilight. The shifts in size, shape, and location of these tombs mirror larger political movements within the Yamato court, making the area what scholars call "a microcosm of the political dynamics of the Kofun era."

Where History Meets Landscape

The Otokuni region occupies the western edge of the Kyoto Basin, along the right bank of the Katsura River. In ancient times, this corridor was a vital transportation hub linking the Yamato heartland to the Sea of Japan. The fertile plains, river crossings, and elevated ridges made it both an attractive place to settle and a strategic location to govern. The name "Otokuni" itself appears in the Nihon Shoki, Japan's eighth-century chronicle, suggesting the area's deep importance to early Japanese identity.

From the mid-3rd century onward, local chieftains began constructing large earthen mounds for their burials, and they continued doing so for over four hundred years. While many of the smaller mounds in the area have been lost to centuries of farming, urban development, and the construction of the Nagaoka-kyō palace in the late 8th century, thirteen of the most significant chieftain tombs have survived and now form this protected historic site.

Why the Otokuni Kofun Group Was Designated a National Historic Site

In March 2016, the national government brought together eleven previously documented mounds under the unified designation "Otokuni Kofun Group." Two more—Chōhōji Minamihara Kofun and Shiba Kofun—were added in February 2018, bringing the total to thirteen. The designation recognized several rare and valuable qualities of the site.

First, the continuous sequence is virtually unmatched elsewhere in Japan. Most regions saw mound construction rise and fade within a generation or two, but in Otokuni, the practice continued without significant interruption from the very earliest Kofun period through to its terminal phase. Second, the changes in tomb shape, scale, and burial goods directly parallel the changes occurring at the great royal tombs of the Yamato court in Nara and Osaka. By studying Otokuni, archaeologists can read the political weather of ancient Japan. Third, several of the mounds preserve features—construction techniques, chamber styles, and grave goods—that are considered standard reference materials for understanding the entire Kofun period.

The Thirteen Mounds: A Walk Through Four Centuries

Each of the thirteen mounds tells its own chapter of the story. Visiting them in chronological order offers an extraordinary view of how power shifted, consolidated, and finally faded in this region.

Highlights and What to See

Several of the thirteen mounds have been carefully restored and developed as parks where visitors can walk among the ancient burial features.

At Egenoyama Kofun Park in Nagaokakyō, a beautifully reconstructed keyhole mound rises beside walking paths lined with replica clay haniwa figures. The mound is so well preserved that it can be seen from passing trains on the JR line. The park also includes interpretive panels explaining the discovery of the iron weapon cache. Curiously, the rear circular section was used as a hilltop fortification by Akechi Mitsuhide during the famous Battle of Yamazaki in 1582, layering Japan's medieval history on top of its ancient past.

Tennō no Mori Kofun opened as a public park in 1994 and remains one of the best-preserved keyhole mounds within Kyoto City. Its tree-shaded paths and quiet atmosphere make it a peaceful detour from the bustle of central Kyoto.

Mozume Kurumazuka Kofun draws visitors particularly during its springtime stone chamber openings (typically late May to early June), when the dim, lit interior reveals the carefully assembled tuff sarcophagus and rare gilt-bronze grave goods that hint at the buried chieftain's connection to Emperor Keitai's court.

Motoinari Kofun sits within Katsuyama Park immediately north of Mukō Shrine and can be visited at any time. Several of the smaller mounds, while not always accessible due to private land or natural overgrowth, can be appreciated from designated viewpoints. Excavated artifacts from across the group are exhibited at the Mukō City Cultural Resource Museum, the Nagaokakyō City Center for Buried Cultural Properties, the Kyoto Prefectural Yamashiro Folk Resources Museum, and the Kyoto University Museum.

The Surrounding Area

The Otokuni region rewards travelers who linger. Mukō Shrine, just steps from Motoinari Kofun, is one of the area's oldest sacred sites and offers fine views over the Kyoto Basin. The bamboo groves of Take no Michi (the Bamboo Path) in Mukō are some of the most photogenic in Japan and lead naturally toward several of the mounds. Long-tailed elegant bamboo arches form a quiet, green tunnel that feels worlds away from urban Kyoto.

In Ōyamazaki, Mount Tennō—site of the decisive 1582 battle between Akechi Mitsuhide and Toyotomi Hideyoshi—is a short hike with panoramic views of the river confluence below. Asahi Beer Ōyamazaki Villa Museum, a Taishō-era estate restored with a Tadao Ando-designed annex, displays an exceptional collection of paintings, including works by Monet. The Suntory Yamazaki Distillery, Japan's first whisky distillery, is also nearby and offers tours by reservation. Nagaokakyō is famous for its Hachijōgahana bamboo shoots, served as a seasonal delicacy at local restaurants in spring.