Midori City Ōmama Museum, commonly known as the Conodont Museum, is a registered museum located in Ōmama Town, Midori City, Gunma Prefecture. The museum introduces the rich natural environment around the southeastern foothills of Mount Akagi as well as the history of the local community from the Jōmon Period through the modern era.
The museum’s nickname comes from Shingo Hayashi, a researcher from Ōmama who was the first person in Japan to discover conodont fossils. The name reflects the area’s significance as an early center of conodont research in Japan.
With exhibits covering natural history, folklore, and local history, the museum offers visitors an opportunity to explore the region from several different perspectives.
The museum itself is housed in a historic building originally constructed in 1921 as the head office of Ōmama Bank.
The two-story building combines a wooden structural frame with Ōya stone construction and tiled exterior walls, giving it a substantial and distinctive appearance. It was designed by Rikio Kobayashi, who was also involved in the design of the Silk-Twisting Memorial Hall.
The building was designated an Important Cultural Property by the former Ōmama Town in 1995 and continues to preserve much of its original atmosphere.
After the Gunma Bank Ōmama Branch moved to a new location in 1986, the historic building was renovated and reopened as a history and folklore museum on April 29, 1988.
The dignified architecture of the former bank, together with its distinctly Taishō-era atmosphere, is itself one of the museum’s attractions.
The Natural History Exhibition Room on the first floor features dioramas of plants and animals found around the Ōmama area, dinosaur models, and exhibits dedicated to the microscopic fossils that have become the museum’s symbol: conodonts.
Conodonts are tiny tooth-like fossils of extinct organisms that lived from the Paleozoic to the Mesozoic Era. Because they can be used as important indicators for determining the age of geological strata, they are valuable to researchers studying Earth’s history.
The exhibits explain how clues about enormous periods of geological history can be obtained from fossils so small that they are difficult to see with the naked eye.
The Folklore Exhibition Room is located in a traditional earthen storehouse that was originally used as a collateral storage building by the former bank. It contains a wide range of tools and household objects associated with life in farming villages and merchant households.
One section recreates a room in a traditional town house, displaying objects such as wooden chests, a wall clock, a charcoal brazier, an abacus, and oil lamps. Together, these objects create an atmosphere that feels like stepping back into an earlier era.
Everyday implements such as the wooden mallet and mortar used for pounding rice cakes also provide a glimpse into the practical knowledge and ingenuity of people in the past.
Ōmama flourished from the Edo Period onward as an important stop along the Akagane Kaidō, the historic copper route connecting the Ashio Copper Mine with Edo, present-day Tokyo. Exhibits also introduce the merchant culture that developed in the town, along with tools once used by dyers, tabi sock makers, blacksmiths, and other local craftsmen.
Displays of traditional firefighting equipment reveal another aspect of the town’s history and the challenges its residents faced in protecting their community from fires.
A reconstructed tsurube well, operated using a bucket and rope, illustrates the area’s low groundwater levels and the difficulties local residents once faced in securing water. It also demonstrates the close relationship between the natural environment and everyday life.
The second floor presents the history of Ōmama in chronological order, from the Jōmon Period to the modern era.
Exhibits include pottery and stone arrowheads excavated from the Setogahara Site, burial objects from the Kofun Period, and Sue ware and Haji ware pottery recovered from residential sites dating to the Nara and Heian periods.
The medieval section includes a reconstruction model of Takatsudo Castle, stone monuments known as itabi, and buried coins. The legendary story of the Satomi brothers is also passed down as part of the area’s local heritage.
During the early modern period, Ōmama prospered as an important relay point along the Akagane Kaidō, through which copper from the Ashio Copper Mine was transported toward Edo.
The town also hosted one of the major silk markets in the Kanto region. The scale and reputation of the market were such that its level of activity was recorded in ranking lists, where it was placed at the level of a komusubi, a rank used in sumo wrestling.
The modern history section introduces the development of the raw silk trade following the opening of Yokohama Port, as well as the establishment of schools, construction of irrigation channels, and expansion of the railway network.
The museum also introduces educators involved in the Freedom and People’s Rights Movement and the achievements of other notable figures connected with the local area.
Midori City Ōmama Museum is more than a place for displaying historical objects. By bringing together nature, industry, everyday life, and local culture, it serves as a center for preserving and passing on the collective memory of the community.
Inside a historic bank building from the Taishō era, visitors can explore an unusually broad span of history, from ancient fossils and prehistoric artifacts to traditional lifestyles and the development of modern industries.
For visitors to Midori City, the museum offers an excellent introduction to the rich history and cultural heritage of Ōmama. A visit provides an opportunity to discover how the region’s natural environment, industries, commerce, and everyday life have shaped the community over the centuries.