This beautiful big Tanto is inscribed Choshu ju Yasuyoshi. There are many smith’s by this name listed in Hawley’s from Koto to Shinshinto.
The hada is a gorgeous Itame with some mokume, lots of chikei, and scattered ji-nie. The Hamon is notare in nioi-deki and contains sunagashi and inazuma. The hakikake in the boshi is outstanding. There are horimono bilaterally. The Omote is a Shin no Kurikara or ascending dragon, while the Ura has Goma hashi or chopsticks engraved. The nakago is ubu with sujikai yasurime. The habaki is a silver shonai style. The shirasaya is better than average having ivory hatome at the mekugi ana and Buffalo horn mekugi.
This tanto is most likely the work of Choshu (Funaka) ju Yasuyoshi from Nagato province who was active around 1848. Very little information is known about this smith. He was probably one of the last remaining members of the once famous Nagato Sa school of swordsmiths who flourished in koto times. Choshu Funaka ju Yasuyoshi is rated 10 in Hawleys (YAS 598), which is similar to most shinshinto smiths.
Nagato Province 長門国, often called Chōshū 長州, was at the extreme western end of Honshū, in the area that is today Yamaguchi Prefecture. Nagato bordered on Iwami and Suō Provinces. Nagato was ruled by the Hojo clan up until the restoration of Emperor Meiji. In 1871 Nagato was merged with Suo province to form Yamaguchi Prefecture.
Period: Late Edo period (c. 1850)
Mei: Choshu ju Yasuyoshi
Shape: Hira zukuri
Nagasa: 27.6 cm
Sori: 0 cm
Kasane (thickness): 6.3 mm
Width at ha-machi: 30.1 mm
Nakago condition: Ubu
Nakago shape: Standard with kuri jiri
Nakago length: 9.3 cm
Additional photos can be found here: http://yakiba.com/Tanto_YasuYoshi.htm