Tombs of a Line of Chiefs in Zentsuji
The Arioka Kofun Group (有岡古墳群) is a group of tombs in Zentsuji City, Kagawa Prefecture, thought to be those of a single line of chiefs, designated a Historic Site in 1984.
The Agency for Cultural Affairs lists it under the criterion for shell mounds, settlements, tombs and similar sites; its photographs record the Nodain, Mausuyama, Tsurugamine No. 4, Maruyama, Obozan and Miyagao tombs.
Zentsuji City notes that some 400 tombs are known in the city, and that the Arioka group is said to be the burial ground of the clan from which Kobo Daishi descended.
The Tombs
According to Zentsuji City, the Nodain Kofun is a keyhole tomb 44.5 metres long from the late third century, in a hollow 400 metres up Mount Oasa. Its rear mound is built entirely of stones, and excavation from 1997 found a second chamber with glass beads, an iron sword and earthenware.
The Obozan Kofun is a keyhole tomb 46 metres long from the mid-sixth century. Its corridor-style chamber yielded a gilt-bronze cap and an iron sword inlaid with silver. It is laid out as a historic park where visitors can walk round and climb the mound.
What to Look For
From the late-third-century Nodain Kofun to the mid-sixth-century Obozan Kofun, the group shows chiefs' tombs being built in the same area over a long period.
Zentsuji City says the Obozan finds are displayed at the city folk museum.
Visiting the Arioka Kofun Group
Zentsuji City notes that the Obozan Kofun is a historic park. For the Nodain Kofun, take the forest road toward Mount Oasa from the signboard by Taru Pond at the southern foot of Tsurugamine.
Enquiries go to the Zentsuji City board of education.
Q&A
- When was the Arioka group designated?
- On 29 November 1984.
- What is distinctive about it?
- It gathers tombs thought to belong to one line of chiefs.
- When was the Nodain Kofun built?
- In the late third century, according to Zentsuji City.
- What was found at Obozan?
- A gilt-bronze cap and a silver-inlaid iron sword.
- Can I climb the Obozan Kofun?
- Yes, it is a historic park.
Basic Information
| Name | Arioka Kofun Group (有岡古墳群) |
|---|---|
| Location | Zentsuji City, Kagawa Prefecture |
| Designation | Historic Site |
| Year Designated | Designated 1984/11/29 (Showa 59) |
| Quantity | Several tombs |
| Dimensions | Nodain Kofun 44.5 metres, Obozan Kofun 46 metres long (Zentsuji City) |
| Owner | Not recorded in the Agency for Cultural Affairs database |
| Public Access | Obozan Kofun is a historic park |
References
- Agency for Cultural Affairs Database: Arioka Kofun Group (Japanese)
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/2527
- Cultural Heritage Online: Arioka Kofun Group (Japanese)
- https://online.bunka.go.jp/heritages/detail/202756
- Zentsuji City: Arioka Kofun Group (Japanese)
- https://www.city.zentsuji.kagawa.jp/soshiki/50/ariokaindex.html
Last verified: 2026.09.28