The earliest dated work that survives under this smith's hand is a inscribed 'ei 2, 1625, and the seven blades gathered here, all signed Izumi no Kami or Izumi no Kami Fujiwara Kaneshige, are the work of the alone. The published sources place him directly after the Yasutsugu and Hankei as the next smith of consequence; tradition holds that he came from , where he had been a yanone-kaji, a maker of arrowheads, before going to and turning to forging blades, an account the Kokon Kajibikō preserves. He is rated Jō- by Fujishiro, and by long tradition he is the teacher of Nagasone Kotetsu. The name carries a second smith after him, his pupil Kazusa no , also Kazusa no Kami, Fujiwara Kaneshige, and the two were for centuries treated as a single man, the change of title explained as deference to his lord Tōdō Izumi no Kami. The published sources set that story aside: signed and age-stated works, among them a of 6, 1666, show the younger smith was born in 'ei 3, 1626, while the elder already bears 'ei dates, so the two are different individuals, and this profile is the first generation only.
The published sources draw his range as two manners, and the distinction governs how his work is read. The first is a -based temper carrying linked , with entering well, the deep and the laid thick, and in his fullest pieces fine and running through the band with patches of coarser , the bright and clear. On a of this manner the published sources find the workmanship so close to Kotetsu that it recalls him at a glance, 「一見徹を髣髴させる作域」, and read in the hardened edge a sense of strength and spirit. The second manner is a base, sometimes a wide straight temper bearing the faintest and sometimes a of almost no movement at all, the deep and the well gathered, with a slight at the and a bright, clearly defined . The constant across both is that clarity of the , the quality the published sources tie to his Kotetsu-like character and name as the mark of Kaneshige at his best.
The beneath both manners is a , closely and well forged, with fine laid thickly and entering, in places flowing into and tending slightly to stand, mixed in here and there. It is the controlled urban steel of an master, the faint standing of the grain keeping the surface alive without breaking it open. The runs straight to a , the at times long, the point swept with . The is the transitional form of the 'ei and Shōhō years, of standard with a markedly pronounced taper, a retained , rather deep and a compact , which the published sources read as the passage from Keichō to form and offer as a point of appreciation of his shape. The is , finished with file marks already carrying a -like tendency the published sources read as an early prototype of the later ornamental , and the long signature is cut with a fine chisel in a distinctive reisho clerical script of seven characters.
The two manners are registers, not periods, and the published sources name which a given blade exemplifies. The wide- of the 61st session they call a typical example of the former, the - hand, its broad straight band mixed with and conveying an overflowing vigor; the deep- of the 43rd session they call a typical example of the latter, where the runs especially deep and the becomes vividly clear. A third register is form rather than temper: his work is almost wholly and with unseen, so that the broad, of the 31st session is a rare construction in which, the published sources note, its mixed with and bright show his true forte. Even within the - manner there are blades of an entirely pure straight temper, 「純然たる直刃」, as the published sources remark of a Yamano cutting-test , so that the two hands shade into one another rather than dividing his career.
What sets him apart is best stated from his own grounded features. His tell is the pairing of a deep with a bright, clear , carried equally over the calm wide and the more active , and beneath it the densely -laden with its fine and slight standing of the grain. The published sources frame his place in the school through Kotetsu at every turn: he is by tradition the teacher, his and deep in and clear in the Kotetsu manner, and a of his is judged to recall Kotetsu at a glance. The line he founded ran on past him, his pupil Kazusa no carrying it into the years and perfecting the , the rosary-bead temper for which the second generation is best known and which the published sources hold could be mistaken for Kotetsu, so that the 's restrained two manners stand at the head of a school whose later fame rests on a temper he himself did not work. Recent study has gone to sorting the two hands apart, by which the elder's seven blades here are now read as the first generation's alone.
Kaneshige is among the leading names, and the 's reputation is inseparable from the cutting-tests that ride on his blades. Two of the seven here carry the gold-inlaid of Yamano Kanjūrō, the name the great tester Kaemon used before the Shōhō era, recording a mitsu-dō three-body cut felled in two strokes and the inscription 「前代未聞剣 山野勘十郎切之」, an unprecedented sharpness cut by Yamano Kanjūrō, a provenance as much as an honor. On record under his name stand seven blades at the rank and no higher designation, almost all and , with no National Treasure or Important Cultural Property among them and no recorded provenance, which is to say that what survives of him is the designated blade rather than the museum-held icon. These are held mostly in long-standing private collections and come to market only from time to time, a signed Kaneshige bearing one of the famous Yamano cutting-test inscriptions the example most sought. He is not beyond the reach of a patient collector, but a piece of his, and above all one carrying the Yamano inlay, is a landmark when it appears.