Itokoku History Museum

The Itokoku History Museum (伊都国歴史博物館, Ito-koku Rekishi Hakubutsukan) is a municipal museum in Itoshima, Fukuoka Prefecture, Japan. Opened in 2004, it focuses on the history of the ancient Ito state and the archaeological heritage of the region. The museum holds approximately 19,500 objects, with particular strength in Yayoi-period materials, and serves as the principal institution for preserving and presenting the cultural properties excavated from the Itoshima area.

The museum's origins trace to the Ito Historical Museum (伊都歴史資料館, Ito Rekishi Shiryōkan), which opened in July 1987. The archaeologist Dairoku Harada, who had made significant contributions to excavations at the Hirabaru site, was originally intended to lead this institution, but he died during the preparation and opening phase. In his honor, a bronze statue was erected, which still stands behind the original building. On 29 October 2004, the institution reopened under its present name as a museum of the city of Maebaru. Following the merger of the cities of Maebaru, Nijō, and Shima into the new city of Itoshima, the museum passed into municipal ownership of Itoshima.

The collection numbers some 19,500 objects, with a primary focus on cultural properties excavated from the Itoshima area. The holdings are particularly strong in Yayoi-period archaeological materials. A central emphasis of the collection is the assemblage from the Hirabaru burial site (平原遺跡), which includes the largest bronze mirror yet discovered, measuring 46.5 cm in diameter and weighing 8 kg. The collection also features numerous comma-shaped and spherical agate beads. In 2006, the contents of a sarcophagus discovered at Hirabaru were designated as a National Treasure, listed as the "Excavated Items from the Hirabaru Square Moated Tomb, Fukuoka Prefecture" (福岡県平原方形周溝墓出土品).

The museum's most celebrated holding is the National Treasure assemblage from the Hirabaru burial site, designated in 2006. This Yayoi-period ensemble includes the extraordinary large bronze mirror, distinguished by its exceptional size at 46.5 cm diameter and 8 kg weight, alongside a significant quantity of comma-shaped and spherical agate beads. These materials represent one of the most important archaeological finds from the Yayoi period in Japan and constitute a designated National Treasure within the category of archaeological materials.

The museum complex comprises an original building and a newer four-story structure. The original building, which housed the Ito Historical Museum, still stands and contains the bronze statue honoring Dairoku Harada on its rear side. The new building was constructed immediately adjacent to the original structure, with the second floor connected by a passageway. The total site area is 14,312 square meters, with 4,119 square meters of interior space and 1,108 square meters of exhibition space.

The Itokoku History Museum is located in Itoshima, Fukuoka Prefecture, Japan. It operates as a municipal museum under the city of Itoshima, having transferred from the former city of Maebaru following municipal consolidation. The museum maintains an official website through the Itoshima city government. Its holdings and exhibitions are accessible to the public, with the National Treasure assemblage from Hirabaru forming a principal attraction for visitors interested in Yayoi-period archaeology and the ancient history of the Ito region.