Oyamazumi Shrine Treasure Hall

Oyamazumi Shrine (Oyamazumi Jinja), located in Omishima, Imabari City, Ehime Prefecture, is the head shrine of all Yamatsumi Shrines and Mishima Shrines throughout Japan, and its Treasure Hall is one of the most important facilities for Japanese sword research, boasting Japan's largest collection of armor and weapons.

Its greatest distinction is the exceptionally high proportion of National Treasures and Important Cultural Properties. Roughly 80% of all armor and weapons designated as National Treasures or Important Cultural Properties nationwide are concentrated here—an unparalleled ratio among Japan's museums and shrines. Specifically, roughly 40% of armor designated as National Treasures or Important Cultural Properties is held in this museum.

The sword collection is especially rich in tachi from the Late Heian through Kamakura periods. The museum houses a peony-and-scrollwork tachi with hyogo-gusari mounts believed to have been dedicated by Moriyo Shinnō and numerous masterwork swords believed to have been dedicated by warriors of the Minamoto (Genji) and Taira (Heike) clans. Since ancient times, Omishima has been revered as the "Guardian Shrine of the Sea," earning the devotion of samurai warriors. For centuries, it was customary for commanders to dedicate prized swords before and after military campaigns—a practice whose accumulated gifts created today's unparalleled collection.

Objects believed to have been dedicated by historical commanders—Minamoto Yoshitsune, Minamoto Yoritomo, Moriyo Shinnō, and the Kōno clan (connected to the Murakami Suigun pirates)—are preserved in the Treasure Hall, making it truly a sacred site of "swords dedicated by samurai." Amid the rich natural surroundings of Omishima, floating in the Seto Inland Sea, and within this historically sacred precinct, visitors can experience the roots of Japanese sword culture.