no Kami Masatoshi was the fourth son of Kanemichi of , founder of the lineage. His elder brothers included Iga no Kami Kinmichi, Kinmichi, and Tanba no Kami Yoshimichi, and together with his father and brothers he relocated from to Kyoto, where they became one of the most influential groups among Kyoto smiths. Although the youngest of the four brothers, Masatoshi was regarded as the most dexterous among them. It is transmitted that he received the provincial title no Kami during the Bunroku era. He was active from the Keicho through 'ei eras; among extant works, the earliest dated example bears the inscription "Keicho 5, second month," while the latest is dated "'ei 6, eighth month." Thereafter his descendants and disciples flourished greatly, ensuring the continuation of the tradition well beyond the master's own working life.
Masatoshi's stylistic range is the broadest within the group, demonstrating that he was an exceedingly versatile craftsman. His oeuvre encompasses works in a -like manner featuring mixed with small ; - in the manner of Kaneshige; pointed reminiscent of the pattern thought to have taken Magoroku Kanemoto as a model; in the style on a forging; and even in the manner. His characteristically shows mixed with and , with the grain standing out, thickly adhering , and fine entering well, frequently presenting a slightly blackish tone to the steel. A recurring hallmark is the appearance of small and forming stripe-like effects above the , from which the budding of a -like tendency can be observed. Additionally, among the so-called that are a hallmark of this lineage, Masatoshi's examples are the most conspicuous: a shallow tendency that thrusts upward to a pointed tip with , forming the characteristic . Carvings are exceedingly rare in his oeuvre, but where they appear they are skillfully executed, and his relief carvings of Fudo Myo-o and constitute precious documentary material for the study of his carving work.
Within the group, Masatoshi may be considered a versatile craftsman comparable to Kunimichi of the school. In addition to faithfully transmitting the traditions of his native province, he worked across the -, , and - idioms with consistently high quality. His and strongly manifest the period character of the and early eras in their wide , thick , and greatly extended , conveying a powerful presence and robust . The complex patterns he favored, overflowing with variation and brilliant activity, together with the thickly adhering , pervasive and , and localized , impart a bold and rustic spirit that recalls an air of antiquity. His works consistently demonstrate that the true forte of the first-generation Masatoshi lies in this union of technical breadth and expressive force, producing blades in which many points of appreciation emerge conspicuously.