Blade construction : Hira-zukuri tanto with an Iori mune. The blade length is 9 sun 8 bu with almost no curvature. It has a broad width and an exceptionally thick in Kasane with a robust and solid form. The kasane (blade thickness) remains thick towards the tip, creating a heavy and powerful impression. The Fukura (blade belly) is slightly subdued, supposed suitable for thrusting. (click HERE for higher resolution photo of the blade)
Engraving (Horimono) : The omote (front side) features twin pararell grooves (Futasuji-hi), while the ura (back side) has a single groove (Bo-hi)
Forging (kitae-hada) : The ko-itame hada (small wood-grain pattern) is well-knit, with thick sparkling Ji-nie (frosted surface) and occasional chikei (fine darkish lines), resulting in a beautiful and refined forging texture
Hamon : The tempering pattern, featured with Nioi, starts with a short wavy line (Yakidashi) and transitions into a Chōji midare (long-stalk clove patterns) interspersed with Ko-gunome. The Hamon is filled with nioi, with visible Ashi (downward streaks) and slight Sunagashi (streaming lines) near the base.
Kissaki : The tip features a Chōji-midare hamon that calms towards the Fukura and straightens forming a medium-sized rounded return (Chū-maru) slightly deeper extending to the Mune
Tang (Nakago) : The tang is ubu (unaltered) with a gourd-shaped Mekugi-ana (peg hole). The heel is Kuri-jiri (double-bevelled) in full. The file marks (Yasuri-me) is greatly slanting left diagonal pattern (Ō-sujikai) with additional decorative file marks Kesho-yasuri. The Omote side bears the inscription "Sanshū-jū KUNISUKE" 三州住国佐, while the ura side has the date of year "In the 5th month, Year of the Tiger Kaei 7th" 嘉永七年寅五月日 engraved.
KUKNISUKE 国佐 was a resident smith of Mikawa Province (now eastern Aichi-pref.) signing his works as "Sanshū Fuchū-jū KUNISUKE" 三州府内住国佐 or "Sanshū-jū KUNISUKE" 三州住国佐. A disciple of Koyama Munetsugu 固山宗次. He specialized in the Bizen tradition and was active around the Kaei period. His dated works range from Kaei 5 and 7 to Bunkyū 3. This tanto is an imposing auxiliary blade to a larger katana. With a blade length of 9 sun 8 bu and a notably thick construction, it exudes a sense of heaviness and sturdiness, perfectly suited for thrusting. Its refined steel and long-stalk Chōji hamon reflect KUNISUKE's mastery of the Bizen tradition, learned from his teacher Koyama Munetsugu 固山宗次.
Mikawa Province, the birthplace of Tokugawa Ieyasu, held strategic importance along the Tōkaidō route. Throughout the Edo period, the region upheld the martial spirit and welcomed talented sword smiths. In Kaei 7 (1854), when Perry's second visit to Japan and the signing of the Treaty of Peace and Amity between Japan and the United States marked the nation's turbulent era under an antiforeign sentiment, the demand for long swords and sturdy tanto increased.
Kunisuke 国佐, alongside other Mikawa smiths such as Yoshitatsu 吉達, Yoshimasa 吉正 from Okazaki, and Hiroshige 寛重 from Kariya, were the province's foremost craftsmen.
This tanto comes with a silver-foiled era-specific Habaki collar and is preserved in a Shirasaya (plain wooden scabbard).
referece :
Kaunzan Honma and Masanori Ishii, Nihontō Meikan, Yuzankaku, Shōwa 50 (1975)
