Hiyoshigaoka-Akeshi Tumulus Group: A Gateway to the Ancient Tango Kingdom
Nestled in the picturesque Kaya Valley of northern Kyoto Prefecture, the Hiyoshigaoka-Akeshi Tumulus Group (日吉ヶ丘・明石墳墓群) is one of Japan's most remarkable archaeological treasures. Designated as a National Historic Site in 2005, this extraordinary burial complex spans from the middle Yayoi period to the early Kofun period — a timeline of over 500 years that reveals the rise and flourishing of one of ancient Japan's most powerful regional centers. For visitors with an interest in Japan's deep prehistory, this site offers a rare and intimate window into an era long before samurai, temples, and the familiar icons of Japanese culture.
What Is the Hiyoshigaoka-Akeshi Tumulus Group?
The Hiyoshigaoka-Akeshi Tumulus Group consists of two distinct archaeological areas located in the town of Yosano, at the southern base of the Tango Peninsula. The Hiyoshigaoka area features a massive stone-clad rectangular tomb (方形貼石墓, hōkei hari-ishi-bo) from the middle Yayoi period, around the 2nd to 1st century BCE. The Akeshi area, situated on higher ground behind the Hiyoshigaoka site, contains 28 burial mounds dating from the late Yayoi to the early Kofun period. Together, these sites document a continuous lineage of powerful chieftains who ruled the Kaya Valley for centuries.
The surrounding area is exceptionally rich in archaeological heritage. Nearby stand the Ebisuyama Kofun, one of the "Three Great Tumuli of the Sea of Japan" at 145 meters in length, and the Tsukuriyama Kofun Group — both designated as National Historic Sites. The Hiyoshigaoka-Akeshi complex adds an earlier chapter to this remarkable story, pushing the known history of Tango's powerful ruling class back by more than 400 years.
Why Was It Designated as a National Historic Site?
The Hiyoshigaoka-Akeshi Tumulus Group was designated as a National Historic Site in 2005 for several compelling reasons. The site provides critical evidence for understanding the social structure and political evolution of the Tango region from the Yayoi through the early Kofun periods. It is especially significant because of the following features:
The Hiyoshigaoka rectangular stone-clad tomb is the largest of its kind ever discovered in Japan. Measuring approximately 32 meters long, 20 meters wide, and standing about 2.7 meters high, this tomb dwarfs all comparable structures from the same era. Its construction technique — flat stones carefully affixed to the upper slopes of the burial mound — connects the Tango region not to the mainstream Kinki (Osaka-Nara) cultural sphere but to the distant Iwami and Izumo regions along the San'in coast. This unexpected cultural link suggests that the rulers of the Kaya Valley maintained trade and diplomatic connections across the Sea of Japan.
A single wooden coffin was discovered near the center of the mound, accompanied by an astonishing collection of over 670 tubular jade beads (管玉, kudatama) and red cinnabar pigment (水銀朱, suigin-shu). These grave goods indicate that the occupant was a person of extraordinary status. The red pigment, associated with spiritual power and preservation rituals, and the exceptional quantity of jade beads together point to a powerful chieftain or king — likely the earliest known ruler of the ancient Tango kingdom.
The 28 tombs in the Akeshi area demonstrate continuity of elite burial practices over several centuries, providing a rare archaeological sequence that illuminates how regional power structures evolved as Japan transitioned from the Yayoi to the Kofun period.
Highlights and What to See
Visitors to the Hiyoshigaoka-Akeshi area can experience the physical landscape where ancient rulers chose to build their monuments. The Hiyoshigaoka site occupies the tip of a low hill overlooking the Noda River and the broad Kaya Valley — a commanding position that would have symbolized the authority of the buried chieftain. While the burial mound itself is preserved in situ, visitors can appreciate the scale of the structure and imagine the flat stones that once adorned its slopes.
For a richer experience, the nearby Yosano Municipal Kofun Park (古墳公園) is an essential companion stop. This open-air park features the fully restored Ebisuyama Kofun and Tsukuriyama Kofun Group, where visitors can walk atop reconstructed burial mounds, see actual stone coffins preserved under protective shelters, and explore the Haniwa Museum. The museum displays haniwa clay figures, pottery, jade beads, and other artifacts excavated from the surrounding tombs, providing invaluable context for understanding the Hiyoshigaoka-Akeshi site.
The Kaya Valley itself is a beautiful setting, with the gentle slopes of the Ōe Mountain Range forming a scenic backdrop. The combination of ancient monuments and pastoral countryside makes this an unforgettable destination for history-loving travelers.
Exploring the Surroundings
The town of Yosano offers much more than ancient tombs. The Chirimen Kaido (ちりめん街道) is a beautifully preserved historic streetscape that tells the story of the Tango chirimen silk crepe industry, which flourished from the Edo period through the early 20th century. Merchant houses, old banks, clinics, and weaving workshops from the Meiji, Taisho, and Showa eras line the atmospheric lanes, offering a fascinating journey through Japan's modernization.
The famous Amanohashidate sandbar, one of Japan's Three Scenic Views, is easily accessible from Yosano. The Ōuchi Pass offers a striking panoramic view of the sandbar stretching across Miyazu Bay. Visitors can also enjoy the local cuisine, including fresh seafood from the Sea of Japan, and explore the sake breweries of Yosano, which craft their products using locally grown rice and pure mountain water.
For those interested in extending their archaeological tour, the Kyotango area to the north features the other two of the "Three Great Tumuli of the Sea of Japan" — the Aminochōzanyama Kofun and the Shinmeiyama Kofun — creating a compelling route through ancient Tango's burial landscape.
Q＆A
- How do I get to the Hiyoshigaoka-Akeshi Tumulus Group?
- Take the Kyoto Tango Railway (Tantetsu) to Yosano Station, then a taxi ride of about 10–15 minutes. If driving, exit the San'in-Kinki Expressway at the Yosa-Amanohashidate IC and head south on National Route 176 for about 10 minutes.
- Is there an admission fee?
- The tumulus site itself can be viewed freely. The adjacent Yosano Municipal Kofun Park and Haniwa Museum charge an admission fee of 300 yen for adults and 150 yen for children.
- Are there English explanations or guides available?
- Signage at the site is primarily in Japanese. The Haniwa Museum has some visual displays that are accessible to non-Japanese speakers. The Yosano Tourism Association offers guided tours by local "Kataribe" storytellers, though these are conducted in Japanese. It is recommended to research the site before visiting or to travel with a Japanese-speaking companion.
- What is the best season to visit?
- Spring (April–May) and autumn (October–November) are ideal, offering comfortable weather and beautiful scenery in the Kaya Valley. The Kofun Park is open year-round but has reduced hours in winter (December–February). Note that the park is closed on Mondays (or the following day if Monday is a holiday).
- Can I see the actual jade beads and artifacts from the Hiyoshigaoka tomb?
- Selected artifacts from the Hiyoshigaoka-Akeshi site are displayed at the Haniwa Museum within the Yosano Municipal Kofun Park. The museum also periodically exhibits the Important Cultural Property glass bracelet (ガラス釧) from the nearby Ōfurominami Kofun, so it is worth checking the exhibition schedule before your visit.
Basic Information
| Name | Hiyoshigaoka-Akeshi Tumulus Group (日吉ヶ丘・明石墳墓群) |
|---|---|
| Designation | National Historic Site (designated 2005) |
| Period | Middle Yayoi period to Early Kofun period (approx. 2nd century BCE – 4th century CE) |
| Location | Akeshi, Yosano-cho, Yosa-gun, Kyoto Prefecture, Japan |
| Hiyoshigaoka Tomb Dimensions | Approx. 32m × 20m, height approx. 2.7m (largest stone-clad rectangular tomb in Japan) |
| Akeshi Area | 28 burial mounds on a hillside at 40–96m elevation |
| Key Artifacts | Over 670 tubular jade beads (kudatama), red cinnabar pigment (mercury vermilion), Yayoi pottery |
| Nearby Facilities | Yosano Municipal Kofun Park & Haniwa Museum (admission: 300 yen adults / 150 yen children) |
| Access | Kyoto Tango Railway "Yosano Station" → taxi approx. 10 min; or Yosa-Amanohashidate IC → Route 176 south approx. 10 min |
References
- 日吉ヶ丘・明石墳墓群 – Cultural Heritage Online (文化遺産オンライン)
- https://bunka.nii.ac.jp/heritages/detail/140447
- 日吉ヶ丘-明石墳墓群 – Kotobank (コトバンク)
- https://kotobank.jp/word/日吉ヶ丘-明石墳墓群-1444879
- 遺跡編（52）日吉ケ丘遺跡（京都府与謝野町） – Kyoto Shimbun
- https://www.kyoto-np.co.jp/articles/-/34608
- 古墳公園はにわ資料館 – Yosano Town Official Website
- https://www.town.yosano.lg.jp/facility-info/leisure-sightseeing-hotel/tourist-facility/403/
- 与謝野町立古墳公園 – Yosano Tourism Association
- https://yosano-kankou.net/kankou/kofunpark/
- 与謝野町立古墳公園 – Umi no Kyoto (Sea of Kyoto Tourism)
- https://www.uminokyoto.jp/spot/detail.php?sid=11
Last verified: 2026.03.02