* Image is for illustrative purposes only.Kodetegashiwa Kanenaga
児手柏包永
Also known as: Kodetegashiwa; the two-faced blade of the Tegai school
Description
Overview — a blade with two faces
Kodetegashiwa Kanenaga is a sword by Kanenaga, a Kamakura-period smith of the Tegai school of Yamato Province. It passed from Hosokawa Yūsai to Tokugawa Ieyasu and was thereafter handed down in the Mito Tokugawa family. Its defining feature is a hamon (temper pattern) that differs completely between the two faces of the blade — the very quality that gave the sword its name. Sources classify it differently: Cultural Heritage Online lists it as a kodachi, while The Tokugawa Museum records it as a tachi.
Workmanship — two hamon on one blade
The blade's most remarkable trait is that the outward-facing side bears a midare (irregular) hamon while the reverse bears a suguha (straight) hamon. Japanese blades are normally tempered to broadly matching patterns on both faces, so this "two-sided" quality has drawn attention since early times. Kanenaga belonged to the Tegai school, one of the five schools of the Yamato tradition, based near the Tegai Gate of Tōdai-ji in Nara and known for the strength of its steel.
Signature
The tang retains the original two-character signature "Kanenaga." Alongside it is an added inscription by Hosokawa Yūsai — "Hyōbu-no-tayū Fujitaka suriage kore, thirteenth day of the third month, Tenshō 2" — recording that Yūsai shortened the blade on that date in 1574. The coexistence of the smith's signature and a later owner's own record on a single tang makes the sword unusually legible as a document of its own transmission.
Provenance — from Hosokawa Yūsai to the Mito Tokugawa
After leaving Hosokawa Yūsai's possession the sword came to Tokugawa Ieyasu, who passed it to his eleventh son, Tokugawa Yorifusa. Yorifusa founded the Mito branch of the Tokugawa house, and the blade was thereafter kept as one of its treasures. It remains the personal property of Tokugawa Narimasa, the fifteenth head of the Mito Tokugawa family.
The Great Kantō Earthquake and survival
The sword was caught in the Great Kantō Earthquake of 1 September 1923 at the Mito Tokugawa residence in Honjo Shin-Koume-chō. It was long believed lost, but in fact the family continued to keep it in its fire-damaged (shōshin) state, and its survival was confirmed in 2015. It is preserved today at The Tokugawa Museum in Mito, Ibaraki Prefecture.
Legends & Stories
The origin of the name "Kodetegashiwa"
The name is said to have been given by Hosokawa Yūsai. He likened the blade's two contrasting faces — a midare hamon on one side, suguha on the other — to the Man'yōshū verse "on Nara hill, the kodetegashiwa, two-faced." The kodetegashiwa (Chinese arborvitae) bears foliage that stands without a distinct front or back, and was long invoked in poetry as a figure for two-facedness. Where most sword sobriquets derive from an owner's name or an anecdote, this one takes the workmanship itself as its source and expresses it through classical verse — a fitting choice for Yūsai, who was celebrated as a poet.
What survives in a burned blade
The Great Kantō Earthquake left the sword shōshin — fire-damaged, its hamon and the activity of its steel impaired. Such blades lose much of their standing as art objects and are often written off as lost, and this one was indeed presumed destroyed for decades. Yet the Mito Tokugawa family never parted with it, and its survival was confirmed in 2015. Still bearing its descent from Ieyasu and the inscription Yūsai had cut into its tang, the sword stands as a reminder that a blade carries more than the beauty of its temper line.