Kunikane, first generation, was of the Hongo family and bore the personal name Genzo, later Yoshinosuke. He claimed descent from the later line of Yamato Hosho Goro and was born in Bunroku 1 (1592) at Kokubun Wakabayashi in Miyagi District, Oshu -- present-day Sendai. He entered the service of Date Masamune as a retained swordsmith (kakae-kaji), and in Keicho 19 (1614), by his lord's command, he traveled to Kyoto and studied under no Kami Masatoshi. In 'ei 3 (1626) he received the court title Yamashiro Daijo. When Masamune died in 'ei 13 (1636), Kunikane likewise took the tonsure, adopting the name Ninzawa Yoe. In Shoho 2 (1645), at the age of fifty-four, he retired and transferred the family headship to the second generation, his eldest son Kichiemon, who would later receive the title Yamashiro no Kami; nevertheless, the first generation continued forging thereafter and died in 4 (1664) at the age of seventy-three. His descendants continued to flourish under the name Kunikane down to the end of the period.
In an era when the tradition was widely practiced among smiths, Kunikane aimed instead for the working range of the Yamato Hosho tradition, and his technique reached a level close to that of the old masters. His manner of work is remarkably consistent throughout his career: he forges in tightly packed with thickly adhering and fine entering abundantly, producing steel that is notably clear. The is a -based temper, typically carrying a shallow tendency, in which uchi-noke, , , and appear along the ; the is deep and adheres well, with and running throughout and a bright, clear . The is characteristically tempered straight and finished in , often showing vigorous . His blades exhibit a high with wide , and a rising from the area is a recognized habit of his workmanship. While the majority of his designated works are and , he also produced of wide and proportions, sometimes bearing such as or carved kaki-nagashi.
Kunikane stands as one of the leading smiths of Oshu. He strove to revive the Yamato Hosho tradition, and his finest works achieve a degree of workmanship that approaches the realm of the old masterpieces. The finely ordered forging, the bright and clear , and the abundance of vertical activity in both and recall the work of Hosho in a manner that few of his contemporaries could equal. It should be noted that signatures reading "Kokubu Wakabayashi" are especially often forged, and thus require careful authentication. Among his extant works, dated examples are comparatively few, making inscriptions of the 'ei era particularly valuable as reference material for the study of his oeuvre.