Onimaru Kunitsuna: The Legend of the Demon Slaying Blade
When travelers think of Japan, images of cherry blossoms, ancient temples, and the gleaming steel of the samurai sword often come to mind. Among the thousands of blades forged throughout Japanese history, five stand above the rest: the Tenka-Goken, or “Five Swords Under Heaven.” Among these legendary artifacts lies the Onimaru Kunitsuna (鬼丸国綱), a national treasure wrapped in a chilling tale of demons and divine intervention.
For culture enthusiasts and history buffs, understanding the Onimaru is not just about appreciating metallurgy; it is about delving into the spiritual belief that objects can possess a soul powerful enough to banish evil.
The Origins of a Masterpiece
The Onimaru Kunitsuna dates back to the early Kamakura period (1185–1333), a time when the samurai class was rising to absolute power. It was forged by Awataguchi Kunitsuna, a master swordsmith from the prestigious Awataguchi school in Kyoto.
The Awataguchi school was renowned for creating elegant, slender blades with active temper lines (hamon). Kunitsuna was the youngest of the six brothers of this school, and his work was highly prized by the shogunate. However, it is not merely the craftsmanship that elevates this sword to mythical status—it is the story of how it earned its name.
The Legend of the Demon Slayer
The name Onimaru translates roughly to “Demon Circle” or “Demon Slayer.” The legend involves Hojo Tokimasa, the first shikken (regent) of the Kamakura shogunate.
According to folklore, Tokimasa was plagued by a debilitating nightmare night after night. In his dreams, a impish demon (oni) would torment him, draining his health and vitality. No medicine or prayer seemed to work. One night, an old man appeared in Tokimasa’s dream—a personification of the sword forged by Kunitsuna. The spirit told Tokimasa that it wished to protect him but was unable to leave its scabbard because it had been neglected and covered in rust. The spirit instructed him to clean the blade.
Desperate for relief, Tokimasa immediately had the sword polished and placed it on a rack in his room. That night, a loud crash woke the household. The sword had fallen from its rack, and upon inspection, they found it had sliced off the leg of a nearby silver brazier (hibachi). The leg of the brazier was carved in the shape of an oni. From that moment on, Tokimasa’s nightmares ceased. The sword had physically cut the “demon” causing the suffering, earning the name Onimaru.
Modern Culture and Significance
Today, the Onimaru Kunitsuna is not just a relic of the past; it remains a potent symbol in Japanese pop culture. It is officially classified as an Imperial Property (Gyobutsu), managed by the Imperial Household Agency. This distinction places it among the most protected artifacts in the nation.
In modern media, the sword has found a new audience through the phenomenon of Touken Ranbu, a popular online game and anime series where famous swords are anthropomorphized into handsome warriors. The character representing Onimaru is depicted as a stern, powerful figure, introducing a new generation to the history of the Kamakura period.
Beyond entertainment, the sword represents the enduring Japanese belief in Tsukumogami—the idea that tools acquire spirits after serving their masters for many years. It stands as a testament to the spiritual bond between the samurai and his blade.
Traveler’s Tips: Seeking the Sword
For travelers hoping to view the Onimaru Kunitsuna, expectations must be managed. Because it is an Imperial Property, it is not on permanent public display. It is housed within the Imperial collection and is only rarely exhibited.
However, sword enthusiasts can still immerse themselves in the culture surrounding it:
- Special Exhibitions: Keep an eye on the schedules for the Tokyo National Museum or the Kyoto National Museum. The Imperial Household Agency occasionally loans the sword for special “Tenka-Goken” exhibitions.
- Kitano Tenmangu Shrine (Kyoto): While Onimaru lives in Tokyo, this shrine houses another of the Five Swords (Onikirimaru) and often holds sword exhibitions in its treasure house. It is a must-visit for blade aficionados.
- The Japanese Sword Museum (Tokyo): Located near the Ryogoku Kokugikan, this museum offers deep insights into the Awataguchi school and the techniques used to create blades like the Onimaru.
- Awataguchi Shrine (Kyoto): Visit the spiritual home of the smiths who forged the blade. It is a quiet, atmospheric spot to pay respects to the history of Japanese metallurgy.
Sources & Further Reading
To deepen your understanding of the legends surrounding the Kamakura period and the Tenka-Goken, the following texts and historical records provide essential context:
- The Taiheiki: A historical epic written in the late 14th century, which chronicles the wars between the Northern and Southern Courts and contains references to legendary blades and the Hojo regency.
- Tokugawa Jikki: The official records of the Tokugawa shogunate, which detail the lineage and ownership of famous swords, including the Onimaru’s passage through the Ashikaga, Oda, and Toyotomi clans.
- Nihon Shoki (Chronicles of Japan): While predating the Onimaru, this classical text establishes the foundational mythology of Oni (demons) and the sacred nature of swords in Shinto belief (such as the Kusanagi-no-Tsurugi).