Antique Japanese Tantō, Unokubi-zukuri, Attributed to Sanjō Yoshinori (三条吉則) — NBTHK Hozon Tōken and Sayagaki by the Renowned Scholar Satō Kanzan

A distinct unokubi-zukuri form with mizuki grooves and a moist, nioi-rich notare hamon, from the patriarch of the Sanjō Yoshinori school of Yamashiro

We are pleased to present a breathtakingly beautiful unokubi-zukuri tantō, accompanied by an NBTHK Hozon Tōken paper (issued August 2024) and a prestigious sayagaki (scabbard inscription) by the renowned sword authority Satō Kanzan, authenticating it as the work of Sanjō Yoshinori (三条吉則).

On the smith — Sanjō Yoshinori (三条吉則)

Active during the Muromachi period in Yamashiro Province (Kyoto), Sanjō Yoshinori is the patriarch of the famed Sanjō Yoshinori school. Alongside Heianjō Nagayoshi (who is historically recorded as the teacher of the famed Muramasa), Yoshinori stands as one of the premier master swordsmiths representing Yamashiro-style blacksmithing in the Muromachi era. While tradition traces the lineage back to Kamakura-period origins, confirmed extant masterworks date primarily from the early Muromachi period (Ōei era onward).

Authentication and attribution

Sayagaki by Satō Kanzan: Authenticated and inscribed on the shirasaya by Dr. Satō Kanzan, one of Japan's foremost modern sword scholars.

NBTHK Hozon paper: Officially certified in August 2024 by the Society for the Preservation of Japanese Art Swords (NBTHK) as a genuine work of Sanjō Yoshinori.

Workmanship and condition

The blade has been exquisitely polished and is in overall sound, high-grade condition, with only a minor, faint 3 mm hairline mark on the ha (cutting edge), approximately 8 cm from the tip on the sashi-ura side. Constructed in the distinctive unokubi-zukuri (cormorant-neck) style, it features mizuki (water-clearing) grooves carved into both sides of the blade. The jigane showcases a finely refined itame-hada, harmonizing with a moist notare hamon rich in nioiguchi. The bōshi gently undulates and turns back into a classic ō-maru.

Form

This unokubi-zukuri blade, with an iori-mune (peaked ridge back), carries a nagasa (edge length) of 38.2 cm and a slight sori (curve) of 0.1 cm, with a motohaba of 25.2 mm and motokasane of 4.6 mm.

The mounting (shirasaya)

The blade is housed in a premium shirasaya, bearing the sayagaki of Dr. Satō Kanzan.

A masterpiece of koto craftsmanship showcasing the distinct unokubi-zukuri form with mizuki grooves, authenticated by both Dr. Satō Kanzan and the NBTHK. An irreplaceable piece for discerning collectors seeking historic Yamashiro art swords.

Specifications

• Type: Tantō (短刀), unokubi-zukuri with iori-mune; ubu, mumei (unsigned); Koto period (Muromachi, Yamashiro Province)
• Smith: Attributed to Sanjō Yoshinori (三条吉則)
• Jigane: Refined itame-hada
• Hamon: Gentle notare with moist nioiguchi
• Length of edge (nagasa): 38.2 cm (approx. 15.04 in / approx. 1 shaku 2 sun 6 bu)
• Curvature (sori): 0.1 cm (approx. 0.04 in)
• Width at base (motohaba): 25.2 mm (approx. 0.99 in)
• Thickness at base (motokasane): 4.6 mm (approx. 0.18 in)
• Peg holes (mekugi-ana): 1
• Weight (blade only): 140 g
• Nakago: Ubu
• Mounting: Shirasaya, with sayagaki by Satō Kanzan
• Certification: NBTHK Hozon Tōken
• Registration No.: Okayama No. 30463 (岡山 第30463号)