A God's Name on a 28-Centimeter Blade
At the Saitama Prefectural Museum of History and Folklore in Omiya, a short blade barely 28 centimeters long carries the name of a deity cut into its steel. This is the tantō signed Bishū Osafune-jū Kagemitsu, dated to the third month of Genkō 3, the year 1323. It is a National Treasure, and one of the most closely studied short swords surviving from the end of the Kamakura period.
The blade is forged hira-zukuri, flat across the face with no central ridgeline, and runs a touch longer than a standard tantō of its day. Its curvature is faint. Five characters reading Chichibu Daibosatsu, the name of a guardian deity, are incised into the front face; a single Sanskrit seed-syllable sits on the reverse. The tang still carries the smith's full signature on one side and the exact date on the other, which fixes the work to a single month seven centuries ago.
Kagemitsu and the Slanted Temper Line
Kagemitsu worked in Osafune, a village on the Yoshii River in Bizen Province, present-day Okayama, that turned out more renowned swordsmiths than anywhere else in medieval Japan. He led the Osafune school in its third generation, following the founder Mitsutada and Mitsutada's son Nagamitsu, and he trained his own son Kanemitsu to continue the line. Dated blades from his hand survive across nearly three decades, from 1306 into the 1330s.
What names Kagemitsu at a glance is the temper pattern he favored, called kataochi-gunome. Most smiths arranged the hardened edge in rounded waves. Kagemitsu pushed each wave so that one side drops away sharply, giving the line a slanted, almost saw-toothed regularity. On this tantō the kataochi-gunome runs even and disciplined, with fine activity worked inside the temper and a soft band of utsuri standing in the steel above it.
Why It Is a National Treasure
The short sword was classed an Important Cultural Property in 1952 and raised to National Treasure in 1956. An earlier designation as an Important Art Object dates to 1937, before the postwar protection system took its current form.
Several qualities set the blade apart. The dated signature settles any question about when it was made, which is uncommon for steel of this age. The tang is ubu, never shortened, so the sword keeps the proportions Kagemitsu intended rather than a later owner's. The carved deity name and seed-syllable are rare on a working blade and root the object in a specific religious purpose. Sources disagree on which deity the reverse syllable stands for, naming either Daiitoku Myōō, a wrathful guardian, or Amida Nyorai; the front inscription, Chichibu Daibosatsu, points to Myōken Bosatsu, the star deity enshrined at Chichibu Shrine in western Saitama. The mounting that accompanies the blade, made around the sixteenth century, is itself part of the designation.
From a Shrine to a Warlord
The blade goes by a second name, Kenshin Kagemitsu, after the warlord Uesugi Kenshin (1530–1578), who is said to have kept it at his side. It appears in the Uesugi family's sword register among the swords recorded as Kenshin's personal blades. Before it reached the Uesugi, tradition holds that the tantō was offered to Chichibu Shrine, which would account for the deity's name on its face. It stayed with the Uesugi house into the modern era, passed afterward to the Okano family, and is now owned by Saitama Prefecture.
The same museum keeps a second Kagemitsu National Treasure, a long tachi the smith produced with his associate Kagemasa in 1329 for a Musashi warrior of the Ōkawara family. The two blades are occasionally shown together.
What to Look For
Up close, the kataochi-gunome rewards a slow look. Tilt your eyes along the edge and the slanted teeth of the temper line catch the light one after another, each falling the same way. The carvings repay attention as well: the deity name is cut cleanly into the flat of the blade, and the seed-syllable on the reverse is small and deliberate.
Find the tang in the display if you can. It curves gently into the shape collectors call furisode, after the long sleeve of a kimono, and ends in a rounded kuri-jiri. The two peg-holes and the file marks remain as Kagemitsu left them. When the mounting is shown alongside, look for the black-lacquer scabbard and the small metal fittings worked with autumn grasses in colored alloy.
Around the Museum
The museum sits inside Omiya Park, on its wooded north side, a five-minute walk from Omiya-kōen Station on the Tobu Urban Park Line and two stops from Omiya, a major junction on the Tokyo rail network. The park is among the oldest public parks in the prefecture.
Within easy reach are Musashi Ichinomiya Hikawa Shrine, head of some 280 Hikawa shrines and the source of the Omiya place name, its approach road running close to two kilometers; the Omiya Bonsai Village and its dedicated bonsai art museum, a short walk north; and the Railway Museum, one of the largest in Japan, a few minutes away on the New Shuttle line. A half-day pairs the sword comfortably with at least one of these.
- 📍 Plan Your Visit to Saitama
- Find tours, activities & transport passes near Short Sword〈Inscribed by Kagemitsu Osafune in Bishu/March
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Q&A
- Can I see the sword whenever I visit?
- No. The tantō is light-sensitive and fragile, so it goes on view only for limited periods, usually about once a year and often in winter. Check the museum's exhibition schedule before you travel.
- Why is it called Kenshin Kagemitsu?
- It takes its name from Uesugi Kenshin, the sixteenth-century warlord recorded as having kept it among his personal swords. Kagemitsu is the swordsmith who forged it.
- What does kataochi-gunome mean?
- It is the temper pattern Kagemitsu is known for. The hardened waves along the edge lean to one side so that each drops away sharply, producing a slanted, regular rhythm that marks out his work.
- What is carved on the blade?
- The front carries the name Chichibu Daibosatsu, a guardian deity linked to Chichibu Shrine; the reverse holds a single Sanskrit seed-syllable. The carvings suggest the blade was made as a dedicatory offering.
- How do I get there, and what does it cost?
- Take the Tobu Urban Park Line to Omiya-kōen Station, then walk five minutes. Permanent-exhibition admission is modest, with higher rates for special exhibitions. Children of junior-high age and younger enter free.
Basic Information
| Official name | Tantō, signed Bishū Osafune-jū Kagemitsu / Genkō 3, third month (known as Kenshin Kagemitsu) |
|---|---|
| Designation | National Treasure (crafts). Important Cultural Property 19 July 1952; National Treasure 28 June 1956 |
| Date | Genkō 3 (1323), late Kamakura period |
| Smith | Osafune Kagemitsu, Bizen Province |
| Form | Hira-zukuri tantō; blade length about 28.3 cm; slight curvature |
| Count | 1 piece, with a chiisagatana mounting included in the designation as an accessory |
| Owner | Saitama Prefecture |
| Location | Saitama Prefectural Museum of History and Folklore, 4-219 Takahana-chō, Ōmiya-ku, Saitama City, Saitama |
| Access | 5-minute walk from Ōmiya-kōen Station (Tobu Urban Park Line) |
| Viewing | Displayed periodically, often in winter; confirm the current schedule before visiting |
References
- Agency for Cultural Affairs, National Cultural Properties Database (Tantō, Bishū Osafune-jū Kagemitsu)
- https://kunishitei.bunka.go.jp/bsys/maindetails/201/476
- Cultural Heritage Online (National Institutes for Cultural Heritage)
- https://bunka.nii.ac.jp/heritages/detail/150061
- Saitama Prefectural Museum of History and Folklore, hours and admission
- https://saitama-rekimin.spec.ed.jp/kyuukanbi_kaikanjikan_kanrannryou
- Saitama Prefectural Museum of History and Folklore, access
- https://saitama-rekimin.spec.ed.jp/access
Last verified: 2026.06.08