A Single Lot of Archaeological Material, National Treasure since 2006
Items Excavated from the Hirabaru Rectangular Moated Tomb, Fukuoka Prefecture (福岡県平原方形周溝墓出土品, Fukuoka-ken Hirabaru Hokei Shukobo Shutsudohin) are Yayoi-period archaeological material at 916 Oaza Iwara, Maebaru City, Fukuoka Prefecture, made an Important Cultural Property on 29 June 1990 and designated a National Treasure on 9 June 2006. The owner is the state through the Agency for Cultural Affairs.
The quantity reads as one lot, after the Inariyama and Fujinoki finds: the third such case. For archaeological material, giving no number has become settled practice.
The period is Yayoi. Archaeological material here has so far been of the Kofun period; this is the first from the Yayoi.
Body and Appendage Divided by Where Things Were Found
What matters most here is how the appendage is separated.
The Agency writes that the property consists of the bronze mirrors, beads and other grave goods excavated from the central burial, while objects from the surrounding ditch, from pits and from elsewhere are designated as an appendage.
The central burial is the main interment. What came from it forms the property. The surrounding ditch runs around the tomb, and pits are dug hollows. What came from those forms the appendage.
Objects from one and the same tomb are split between body and appendage according to where they were found.
Appendages have taken many forms here. A later document with the Taima Mandara Engi; original court papers with the Sanmyakuinki; a box with the Sarashina Diary; a monk's portrait with the four commanders; a mounting with the Nakatsukasa Masamune. Dividing by findspot rather than by kind of object is new.
Counted as Thirty-Two Mirrors' Worth
How the mirrors are counted is distinctive.
Thirty-two mirrors' worth of one type and seven of another, the record says, rather than thirty-two mirrors and seven mirrors.
The reason stands in the preceding sentence: the bronze mirrors were found broken up, at the four corners of the grave pit.
Found in fragments, they cannot be counted as whole mirrors. Gathering the pieces and stating how many mirrors they amount to is what this form of words does. A third type is recorded simply as one, without that qualification.
The Gobu Shinkan scroll writes a loss into its title, and a sword's title records what cannot be read. Here damage has changed the manner of counting itself.
Surpassing All Others, Stated in the Record
The assessment is worth checking.
Among these grave goods the bronze mirrors number forty in all, a quantity surpassing any other found in a single feature.
Forty from one feature is said to exceed all others. That judgment stands in the Agency's own record.
The oldest surviving Japanese writing, for the Inariyama finds, and the count of nine surviving copies, for the Soranjo, likewise stood in the record. Only three bowls in the world, for the Yohen Tenmoku, and surviving only in Japan, for the Meihoki, did not, and were dropped.
Accounts elsewhere describe the largest bronze mirror in Japan, 46.5 centimetres across. The Agency's record gives no dimensions for any mirror, and this article does not repeat the figure.
The coffin is described too: red pigment and beads in quantity were found within it, along with a single iron sword with a ring pommel.
Seeing It
The material is at 916 Oaza Iwara, Maebaru City, Fukuoka Prefecture, owned by the state. It is a museum holding, not kept on permanent display.
The Agency gives the location as Maebaru City. Accounts elsewhere give Itoshima City. This article follows the record.
The findspot is placed in three steps: within the Sone group of sites, a designated historic site, the Hirabaru site, and within that the rectangular moated tomb that is its first tomb.
Display plans can change, so check the museum's information before travelling.
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Q&A
- When was the material designated?
- It became an Important Cultural Property on 29 June 1990 and a National Treasure on 9 June 2006. The quantity is one lot, the address 916 Oaza Iwara, Maebaru City, and the owner the state.
- How is the appendage separated?
- By findspot. The Agency records that grave goods from the central burial form the property, while objects from the surrounding ditch, pits and elsewhere are the appendage. Material from one tomb is split by where it was found.
- What does mirrors' worth mean?
- A count of how many mirrors the fragments amount to. The mirrors were found broken up at the four corners of the grave pit, so they cannot be counted as whole pieces: thirty-two of one type and seven of another are recorded this way.
- How many mirrors are there?
- The Agency records forty in all, and calls that a quantity surpassing any other found in a single feature.
- Is the largest bronze mirror in Japan among them?
- The Agency's record gives no dimensions for any mirror. Accounts elsewhere cite 46.5 centimetres across, but this article does not repeat that figure.
Basic Information
| Name | Items Excavated from the Hirabaru Rectangular Moated Tomb, Fukuoka Prefecture (福岡県平原方形周溝墓出土品, Fukuoka-ken Hirabaru Hokei Shukobo Shutsudohin) |
|---|---|
| Location | 916 Oaza Iwara, Maebaru City, Fukuoka Prefecture |
| Designation | National Treasure (archaeological material); objects from the surrounding ditch and pits are designated as an appendage |
| Year Designated | 1990 (29 June), Important Cultural Property; 2006 (9 June), National Treasure |
| Quantity | One lot, with no count given |
| Dimensions | The Agency records no dimensions. The bronze mirrors were found broken up at the four corners of the grave pit, amounting to 32 of one type and 7 of another, with 1 more of a third, 40 in all. The period is Yayoi |
| Owner | The state, through the Agency for Cultural Affairs |
| Public Access | Held by a museum, not on permanent display |
References
- Cultural Heritage Online: items from the Hirabaru rectangular moated tomb
- https://bunka.nii.ac.jp/heritages/detail/188462
- Fukuoka Prefecture cultural properties database
- https://www.fukuoka-bunkazai.jp/
- Itoshima City: the Hirabaru site
- https://www.city.itoshima.lg.jp/site/bunkazai/hirabaru-iseki.html
- Agency for Cultural Affairs, National Cultural Properties Database
- https://kunishitei.bunka.go.jp/
Last verified: 2026.09.05