The Kaneshige lineage encompasses two distinct smiths long conflated in the historical record: Izumi no Kami Kaneshige, the first generation, and Kazusa no Kaneshige, the second. Modern scholarship has established that they were "clearly different individuals," with documentary evidence placing Kazusa no 's birth in 'ei 3 (1626). Izumi no Kami Kaneshige was an -based smith who emerged after the first-generation Yasutsugu and Shigekei, with the earliest dated work a inscribed 'ei 2 (1625); tradition records that he was originally an arrowhead smith from . Kazusa no , regarded as either his son or student, was active during the and Enpō eras and was a contemporary of Kotetsu. Like Kotetsu, he specialized in the distinctive style known as , and the observes that "it is not difficult to imagine that Kaneshige's style exerted a substantial influence on Kotetsu's later development of the style."
The two generations share a foundation in deep , well-adhering , and a bright, clear , but their stylistic ranges diverge. Izumi no Kami Kaneshige's works divide into two modes: one based on with accompanying and , and another in which a wide with shallow yields "an unusually thick " and "a vividly bright and clear ." His is typically well-forged with fine, densely applied and ; his signature is cut in a distinctive reisho (clerical-script) style, and his tang bears file marks with a -like tendency regarded as "an early prototype" of the decorative seen on later works. Kazusa no Kaneshige, inheriting and refining his predecessor's manner, established the as his own domain. The tempers running in sequence within a -based composition, with "a fixed rhythm in which a single is tempered, then two, repeating in a one-two alternation" -- a characteristic the identifies as "a major point of appreciation for this smith." Internal activities of and are conspicuous throughout, and the attaches thickly with occasional .
The Kaneshige lineage occupies a pivotal position in the development of early swordmaking. Works by both generations are repeatedly described as recalling "the workmanship associated with Tōru" -- the celebrated Kotetsu -- and the second generation's fully realized on a Manji 4 (1661) is noted as preceding Kotetsu's own development of that style. The transitional of Izumi no Kami's works, moving from Keicho toward , marks a formative moment in the period's aesthetic evolution. Across both generations, the praises the finest examples for workmanship that is "outstanding," for forms that are and filled with vigor, and for cutting performance attested by multiple gold-inlaid by the Yamano school of sword-testers.