Bronze Bell Excavated from the Kamo Iwakura Site in Shimane

Thirty-Nine Bells: The Largest Single Find in Japan

The Bronze Bells Excavated from the Kamo Iwakura Site in Shimane Prefecture (島根県加茂岩倉遺跡出土銅鐸) are thirty-nine Yayoi-period bronze ritual bells recovered in 1996 at Iwakura, Kamo-cho, Unnan City, designated Important Cultural Properties on 7 June 1999 and National Treasures on 10 July 2008. The category is archaeological materials. They belong to the national government and are held by the Shimane Museum of Ancient Izumo.

No other single site in Japan has produced so many. The previous record was twenty-four bells from the Oiwayama site in Yasu, Shiga Prefecture. Around 470 dotaku are known nationwide, distributed mainly through western Japan with the Kinki region at the centre; fifty of them come from Izumo, and the Kamo Iwakura thirty-nine account for most of that.

The find was accidental. On 14 October 1996 a mechanical excavator cutting a farm road struck something that sounded wrong. The operator stopped, and a bell coated in green patina emerged from the soil. A press conference was held that evening, the site was named the following day, and excavation continued into the following year.

Why They Were Designated: Relationships, Not Quantity

The number alone is only part of the citation. What carried more weight is how the thirty-nine relate to one another and to other sites.

Several types are present. Nineteen bells of the earliest flanged-handle type appear alongside flat-handle and ridged-handle types, so the development of the dotaku from the middle to the late Yayoi period can be traced within a single burial pit.

Fifteen sets, twenty-six bells, share moulds. Bells cast from the same mould are called dohan dotaku. Their counterparts are found in Wakayama, Tottori and Hyogo, making the group physical evidence of exchange across western Japan.

Seven carry engraved images. Deer, boar, turtles, softshell turtles and dragonflies are incised into the surfaces. Direct evidence of what Yayoi people chose to depict is not plentiful.

They connect to the Kojindani site three kilometres away. Kojindani produced 358 bronze swords, sixteen bronze spearheads and six bells, and the same X-shaped mark appears on finds from both places. Neither site can be understood without the other.

How They Were Buried: Nested, and Turned the Same Way

The thirty-nine were not tipped into a pit. They were buried nested, a smaller bell placed inside a larger one. Twelve pairs came out still nested and three more are thought to have been so originally. The larger bells run about 45 centimetres, the smaller about 30.

The placement is consistent. Each bell was laid on its side with its flanges pointing up and down, arranged mouth to mouth. CT scanning has shown that soil different from the surrounding fill was packed deliberately inside the bells. Burial itself was a rite with a settled procedure.

Fourteen of the thirty-nine carry an X cut into the handle with a sharp blade. The handle is the loop by which a bell would be suspended. The same mark appears on bronze swords from Kojindani, tying the two sites together. One reading is that the mark sealed the spirit within so it could not return to the surface, and that old ritual equipment was quieted and buried as a new form of ritual took over. This remains an interpretation.

What a Dotaku Is: From Heard to Seen

Dotaku are bell-shaped bronzes made in Japan during the Yayoi period, roughly the third century BCE to the third century CE. Their use is not settled. One view treats them as ritual vessels for prayers for good harvests; another as instruments swung to produce sound.

The form changed markedly. Early bells stand 20 centimetres to 50 centimetres and hold an internal clapper, so they could actually be rung. Later bells lost that function and some exceed a metre in height. The two are distinguished as bells to be heard and bells to be seen.

The Kamo Iwakura group carries two decorative schemes: flowing-water design on nine bells and crossed-band design on thirty. All nine flowing-water bells use the horizontal variant produced by workshops in the southern Kinki region, evidence of contact between Izumo and the capital area. Among the crossed-band bells there are groups thought to come from a single workshop, which helps in reading how production was organised.

The engraved images show regional character. Dragonflies, as creatures of the air, are placed in the upper registers; deer appear to have been regarded as spirits of the land. This treatment is not found elsewhere and is one of the grounds for supposing the bells were made in Izumo.

Seeing Them, and Seeing Where They Were Found

The thirty-nine bells are held by the Shimane Museum of Ancient Izumo, immediately east of Izumo Taisha. In the permanent galleries they stand alongside the 358 swords, sixteen spearheads and six bells from Kojindani, and nowhere else can the relationship between the two sites be checked against the objects themselves.

The museum is closed, however, from April 2025 to September 2026 for seismic work and a redisplay, with reopening planned for October 2026. Workshops and garden events continue during the closure, but the bells cannot be seen. Check the museum's announcements before travelling.

At the find spot stands the Kamo Iwakura Site Guidance Centre. It is built as a bridge across the two sides of a hill cut into a V by the farm road, so the position of the burial pit can be read against the shape of the ground. It opens from 9:00 a.m. to 5:00 p.m., closed on Tuesdays except public holidays and from 29 December to 3 January. Both the site and the centre are free.

From Kamonaka Station on the JR Kisuki Line it is about ten minutes by car, with free parking. Visiting the Kojindani site three kilometres to the northwest in the same trip gives a sense of the distance between two places joined by that X.