Naganobu was the seventeenth descendant of Wakashu Fuyuhiro and he is called Takahashi Rihei. He was of the Chouensai Tsunatoshi school and he became the swordsmith of the Matsue Han. He lived in Edo Kikumachi Hirakawa-cho. He left some works with the mei of Fuyuhiro. There are many of his works with a uniform choji ha with nioi, nie, fukai ashi iri. His style generally resembles that of Tsunatoshi. He left blades with horimono of ken ahd ryu (dragons). He died in Matsue in the eleventh year of Meiji (1878) of May the 27th at the age of 72. He was an excellent smith and is rated as Jo-saku by Fujishiro.
This blade was special ordered by a Yokota Zuiga. It is signed Unshu Takahashi Naganobu Ju Yokota Zuiga Nyudo Kono Ken o Obiru. This means that this tanto was special ordered by Yokota Zuiga. It is dated as being made on Koka Sannen Hachi Gatsu Kichi Nichi. This means made on a lucky day in the eighth month of the third year of Koka (August, 1846). It has a cutting edge of 13 1/8 inches or 33.4 cm. It is hira-zukuri in shape with a flowing itame hada. There is utsuri present. The hamon is an irregular billowing choji that slants both fore and aft with ashi. There is definitely Bizen school influence. If you look closely at the file marks on the nakago (yasurimei) you will note that they are backwards from the norm. This would indicate that this smith was left handed. It is in very good polish with only a few areas of light scratching, easily polished out.
This blade comes with new Tokubetsu Hozon papers attesting to its quality and authenticity. Also this blade was published in Unshu Toko Takahashi Tsumbo Shi Naganobu no Kenkyu on page 301.