no Kami Masatsune was born in Nodo in Province and at first signed with the name Kanetsune. In Eiroku 10 (1567) he established an independent branch of the family and moved to Komaki village, likely adopting the name Masatsune around that time. He received the court title no Kami in Tensho 19 (1591) and in Keicho 5 (1600) followed Matsudaira to Kiyosu in Owari Province, where he forged alongside Hoki no Kami Nobutaka and Hida no Kami Ujifusa -- smiths who came to be known collectively as the Owari Sansaku, the Three Great Smiths of Owari. In Keicho 12 (1607) he took the tonsure and retired, passing the name to his son; however, when the second generation died suddenly two years later, Masatsune returned to active work and forged thereafter under the nyudo- signature "Masatsune Nyudo." He is recorded as having died in Genna 5 (1619) at the age of eighty-four.
Masatsune particularly excelled at and , yet among extant works and are the most numerous and are moreover of high quality, whereas and are extremely few. His characteristic forging is an that overall flows and becomes -inclined, with plentiful and well-formed ; the often displays a pronounced quality while conveying an antique flavor. His tempering centres on in , at times taking on a faint tendency with small mixed in, producing a bright . Carvings, when present, are simple yet crisp and harmonize well with the blade, further tightening and refining the overall impression.
The consistently characterises Masatsune's works as calm and restrained pieces in which his true strengths are demonstrated to the fullest. Even in the rarer examples, where the tempering is bolder and the more profuse, the evaluation notes that he aimed at the work of superior craftsmen of , especially such masters as Sadamune and , while nonetheless revealing his own distinctive characteristics. His , precious as source material given their extreme rarity, display a that enters and is vigorously with a long return -- a hallmark regarded as thoroughly typical workmanship. Across all forms, both and are noted for construction and a brightness that may be counted among the highlights of his oeuvre.