Norishige of the Ko-Bizen school is a smith of Bizen Province active during the late Heian to early Kamakura period, and is entirely distinct from the far better-known Etchu Province Norishige of the Soshu tradition. Ko-Bizen Norishige belongs to the earliest stratum of Bizen work, predating the organized schools of Ichimonji and Osafune. His signed tachi and wakizashi bear a two-character inscription reading "Norishige," cut with a characteristically thick chisel on the ha-omote side toward the mune. Extant signed examples are acknowledged as rare, and several surviving blades have been considerably shortened (suriage), with signatures preserved through the orikaeshi-mei technique of folding the original tang.

The workmanship of Ko-Bizen Norishige displays the hallmark features of the early Bizen group. The jigane shows tight itame-hada with a tendency toward standing grain, and the steel exhibits a quality described as having an utsuri-like appearance -- the faint, shadowy reflection in the ground metal characteristic of classical Bizen forging. The hamon is typically rendered in ko-midare mixed with ko-choji and small gunome, with ashi and yo entering frequently to create a lively, animated temper line. Sunagashi and kinsuji appear within the hardened edge, and nie adheres well throughout. The boshi tends toward midare-komi finishing in yakizume, a construction consistent with the oldest Bizen conventions.

Ko-Bizen Norishige occupies a position of scholarly interest precisely because his surviving corpus is small yet consistently demonstrates the foundational qualities of Bizen-den workmanship. His blades range from compact pieces approaching kodachi proportions to full-length tachi, attesting to a versatile production. The combination of sound preservation, clear internal activity, and the rarity of authenticated signatures makes each confirmed work a significant reference point for understanding the formative period of the Bizen school.