This is a tanto attributed to the Gassan school, specifically categorized as Ko-Gassan from the Muromachi era in Dewa Province. It features the distinctive ayasugi-hada, a traditional forging method of the Gassan smiths. The blade is accompanied by an NBTHK Hozon certificate and is housed in a shirasaya.
Certificate reading — 銘 月山



Wakimono · Dewa · around 1394-1428
Tōken Taikan top 60%
1 piece on the market now
Where Gassan stands among comparable artisans: across all of nihontō, and within tradition, era, and period. The tiers (Foremost · Leading · Major · Notable) weigh official designations from the NBTHK and Japan's Agency for Cultural Affairs, together with historical honors of lasting repute such as the Sansaku and Meibutsu-chō.
Select a lens to see how it's measured.
Wakimono · Dewa
47 pieces on the market now
Mount Gassan rises among the Dewa Sanzan, the three sacred peaks of northern Japan bound to the mountain asceticism of Shugendō, and the swordsmiths who took the mountain's name worked in its shadow in Ōshū, Dewa Province. The setsumei record that smiths signing "Gassan" are noted in the Kanchiin-bon Meizukushi as early as the Heian period, and the lineage's oldest surviving signed blade is a tachi simply signed Gassan, kept at the Gassan Shrine and judged to date from the late Nanbokuchō to early Muromachi period. Learn more →
| Smith | Era | Designated |
|---|---|---|
| Naonori直則 | 1830-1844 | 0 |
| Toshiyasu俊安 | 1504-1521 | 0 |
| Nagahisa長久 | 1334-1338 | 0 |
| Kiyoyasu清安 | 1532-1555 | 0 |
| Tomosada友定 | 1532-1555 | 0 |
Certifies a genuine blade worth preserving: a signature confirmed correct, or, if unsigned, an era, province, and school that the NBTHK can reliably identify.
The NBTHK (Nihon Bijutsu Tōken Hozon Kyōkai, the Society for the Preservation of Japanese Art Swords) is a public-interest incorporated foundation founded in 1948 and supervised by Japan’s Agency for Cultural Affairs (Bunkachō); it is based at the Japanese Sword Museum in Tokyo. Its expert panels physically examine each submitted work (shinsa) and issue a certificate (kanteishō) ranking it by artistic and historical merit. NBTHK papers are the most widely recognized standard of authentication for Japanese swords and fittings.
NBTHK official siteCooling-off (returns or exchanges) is accepted within 3 days of the item's arrival. Return shipping and refund transfer fees are the customer's responsibility. Fees other than the item price (transfer fees, credit card fees, etc.) cannot be refunded. Returns and refunds are not available for overseas destinations.
This is a tanto attributed to the Gassan school, specifically categorized as Ko-Gassan from the Muromachi era in Dewa Province. It features the distinctive ayasugi-hada, a traditional forging method of the Gassan smiths. The blade is accompanied by an NBTHK Hozon certificate and is housed in a shirasaya.
Certificate reading — 銘 月山



Wakimono · Dewa · around 1394-1428
Tōken Taikan top 60%
1 piece on the market now
Where Gassan stands among comparable artisans: across all of nihontō, and within tradition, era, and period. The tiers (Foremost · Leading · Major · Notable) weigh official designations from the NBTHK and Japan's Agency for Cultural Affairs, together with historical honors of lasting repute such as the Sansaku and Meibutsu-chō.
Select a lens to see how it's measured.
Wakimono · Dewa
47 pieces on the market now
Mount Gassan rises among the Dewa Sanzan, the three sacred peaks of northern Japan bound to the mountain asceticism of Shugendō, and the swordsmiths who took the mountain's name worked in its shadow in Ōshū, Dewa Province. The setsumei record that smiths signing "Gassan" are noted in the Kanchiin-bon Meizukushi as early as the Heian period, and the lineage's oldest surviving signed blade is a tachi simply signed Gassan, kept at the Gassan Shrine and judged to date from the late Nanbokuchō to early Muromachi period. Learn more →
| Smith | Era | Designated |
|---|---|---|
| Naonori直則 | 1830-1844 | 0 |
| Toshiyasu俊安 | 1504-1521 | 0 |
| Nagahisa長久 | 1334-1338 | 0 |
| Kiyoyasu清安 | 1532-1555 | 0 |
| Tomosada友定 | 1532-1555 | 0 |
Certifies a genuine blade worth preserving: a signature confirmed correct, or, if unsigned, an era, province, and school that the NBTHK can reliably identify.
The NBTHK (Nihon Bijutsu Tōken Hozon Kyōkai, the Society for the Preservation of Japanese Art Swords) is a public-interest incorporated foundation founded in 1948 and supervised by Japan’s Agency for Cultural Affairs (Bunkachō); it is based at the Japanese Sword Museum in Tokyo. Its expert panels physically examine each submitted work (shinsa) and issue a certificate (kanteishō) ranking it by artistic and historical merit. NBTHK papers are the most widely recognized standard of authentication for Japanese swords and fittings.
NBTHK official siteCooling-off (returns or exchanges) is accepted within 3 days of the item's arrival. Return shipping and refund transfer fees are the customer's responsibility. Fees other than the item price (transfer fees, credit card fees, etc.) cannot be refunded. Returns and refunds are not available for overseas destinations.