Nagato Province Coin-Casting Artifacts: Relics of Japan's Earliest Official Mint

Deep within the collections of the Kyoto National Museum lies a remarkable assemblage of archaeological objects that tell the story of Japan's first steps toward a monetary economy. The Nagato Province Coin-Casting Artifacts (長門国鋳銭遺物, Nagato no Kuni Chūsen Ibutsu) are a group of Important Cultural Properties consisting of coin mold fragments, crucible remnants, and bellows nozzle pieces dating to the Nara period (8th century). Originally unearthed at the Nagato Mint Site in present-day Shimonoseki City, Yamaguchi Prefecture, this particular collection is owned by the Tatsuuma Archaeological Museum and entrusted to the Kyoto National Museum for preservation and study.

These artifacts represent tangible evidence of the production of the Wadō Kaichin (和同開珎), widely regarded as Japan's first officially circulated coinage. For international visitors with an interest in ancient history, numismatics, or the origins of Japanese civilization, these humble yet profoundly significant objects open a window into a pivotal chapter of Japan's past.

Historical Background: The Birth of Japanese Coinage

In the early 8th century, Japan was undergoing a dramatic transformation. Inspired by the governmental systems of Tang Dynasty China, the imperial court sought to establish a centralized state governed by codified law. A critical element of this vision was the creation of an official currency system. In 708 CE, following the discovery of copper deposits in Musashi Province (modern Saitama Prefecture), Empress Genmei ordered the minting of Japan's first official coins — the Wadō Kaichin.

The Wadō Kaichin was modeled after the Chinese Kai Yuan Tong Bao, featuring a round shape with a square hole in the center, a diameter of approximately 2.4 centimeters, and a weight of around 3.75 grams. To produce these coins on a large scale, the government established official minting facilities known as Jusen-shi (鋳銭司) in several provinces, including Nagato (present-day western Yamaguchi Prefecture), Ōmi (Shiga), Kawachi (Osaka), Musashi (Saitama), and others.

The Nagato Mint was particularly significant. Located within the grounds of present-day Kakuonji Temple in the Chōfu district of Shimonoseki, it operated from approximately the Wadō era (708–715) through to around 825 CE, when its functions were transferred to a new facility in Suō Province. The Shoku Nihongi, an official chronicle of the period, records that copper mined and refined at two locations in neighboring Suō Province was sent to Nagato for coin production — confirming the mint's important role in Japan's earliest monetary infrastructure.

What Are the Nagato Coin-Casting Artifacts?

The collection designated as heritage ID 34703 comprises a specific group of artifacts owned by the Tatsuuma Archaeological Museum (公益財団法人辰馬考古資料館), based in Nishinomiya, Hyōgo Prefecture. These objects, currently deposited at the Kyoto National Museum, were originally excavated from the Nagato Mint Site in the Toyoura Village area of Chōfu, Shimonoseki City.

The collection includes the following items:

• Wadō Kaichin Coin Mold Fragments (和同開珎銭笵残欠) — 12 pieces. These are remnants of the stone or clay molds used to cast Wadō Kaichin coins. Known as senhan, these molds bear the negative impressions of the coin design and provide direct evidence of the coin-making process at the Nagato facility.
• Crucible Fragments (坩堝残欠) — 2 pieces. These are portions of the heat-resistant vessels in which copper was melted before being poured into coin molds. The crucibles show evidence of extreme heat exposure, attesting to the industrial nature of the minting operations.
• Bellows Nozzle Fragments (鞴口残欠) — 2 pieces. Known as fuigo-haguchi, these ceramic nozzles were attached to bellows used to force air into the furnace, raising temperatures high enough to melt copper. They are essential components of the ancient metallurgical process.

This collection passed through the hands of the Shimogō Kyōsaikai foundation before being acquired by Tatsuuma Etsuzō, a prominent collector of archaeological materials, in the mid-20th century. All items were designated as Important Cultural Properties of Japan on January 28, 1964.

Why These Artifacts Matter: Cultural Significance

The Nagato Coin-Casting Artifacts hold exceptional importance for several reasons. First, they provide direct physical evidence of Japan's earliest organized monetary production. While historical texts such as the Shoku Nihongi describe the establishment of minting operations, archaeological artifacts like these transform written records into tangible reality.

Second, the Nagato Mint Site is the only confirmed location among the various Wadō Kaichin production sites where archaeological remains have been definitively identified. While other minting facilities are mentioned in historical sources, the Nagato site uniquely preserves both the archaeological context and the physical artifacts of coin production.

Third, these objects illuminate the sophisticated technological processes involved in ancient Japanese metallurgy. The coin molds reveal the precision required to produce standardized currency, while the crucibles and bellows nozzles speak to the industrial infrastructure necessary for large-scale metal casting — techniques that were at the cutting edge of technology in 8th-century Japan.

Finally, the Wadō Kaichin itself represents a profound moment in Japanese cultural history: the point at which Japan began to assert its identity as an independent state through the creation of its own currency, modeled after but distinct from Chinese coins.

Visiting the Artifacts: The Kyoto National Museum

The Tatsuuma Archaeological Museum's collection of Nagato Coin-Casting Artifacts is deposited at the Kyoto National Museum, one of Japan's most prestigious cultural institutions. Located in the historic Higashiyama district of Kyoto, the museum houses an extraordinary collection of Japanese art and archaeological objects spanning millennia.

Please note that as deposited items, the Nagato Coin-Casting Artifacts may not always be on permanent display. The Kyoto National Museum rotates its exhibitions regularly to preserve delicate objects and to present fresh perspectives on its vast collection. Visitors interested in viewing these specific artifacts are advised to check the museum's current exhibition schedule before planning their visit.

The Kyoto National Museum's Heisei Chishinkan (平成知新館), designed by the renowned architect Taniguchi Yoshio, provides a stunning modern setting for the appreciation of Japan's ancient cultural treasures. The building's clean lines and generous use of natural light create an ideal environment for contemplating objects from Japan's distant past.

The Nagato Mint Site: A Journey to Shimonoseki

For visitors who wish to explore the original context of these artifacts, the Nagato Mint Site (長門鋳銭所跡) in Shimonoseki offers a fascinating pilgrimage. The site is located within the grounds of Kakuonji Temple, a beautiful Ōbaku Zen temple founded in 1698 by the Chōfu Mōri clan. A stone monument marks the location of the ancient mint, and interpretive signage explains the site's historical significance.

The companion collection of Nagato Coin-Casting Artifacts owned by the city of Shimonoseki — including a Wadō Kaichin coin, additional mold fragments, crucibles, and bellows nozzles — is housed at the Shimonoseki City Museum of History, located nearby in the charming castle town of Chōfu. This museum, which reopened in 2016 after extensive renovation, offers excellent contextual information about the region's rich history from ancient times through the dramatic events of the Bakumatsu period.

The Chōfu district itself is one of western Japan's most atmospheric historic neighborhoods, with samurai residences, temple gardens, and quiet lanes that invite leisurely exploration.

Surrounding Attractions

Near the Kyoto National Museum

The Kyoto National Museum is situated in one of Kyoto's richest cultural zones. Within easy walking distance, visitors can explore Sanjūsangen-dō, famous for its 1,001 statues of Kannon; Tōfuku-ji Temple, celebrated for its autumn foliage; and the atmospheric streets of Gion. The museum is also close to the Kiyomizu-dera area and the Fushimi Inari Shrine, making it easy to combine a museum visit with broader Kyoto sightseeing.

Near the Nagato Mint Site in Shimonoseki

The Chōfu area of Shimonoseki offers numerous attractions for history enthusiasts. Kōzan-ji Temple, designated as a National Treasure, features one of the finest examples of Kamakura-period Zen architecture in Japan. The Chōfu Garden and the former Mōri residence provide serene spaces for relaxation. The Shimonoseki Strait, separating Honshū from Kyūshū, offers spectacular views and is closely associated with the dramatic final battle of the Genpei War in 1185.