Masahiro was the son of Yoshinobu, a smith of the collateral Hizen line who first signed Masanaga and took the name Masahiro in Kan'ei 2 (1625). He worked at Saga in the orbit of the Hizen Tadayoshi school, served as a close attendant of the second-generation Omi no Daijo Tadahiro, and after the death of the first-generation Tadayoshi assisted the second generation as, in the words of the published sources, a most able collaborator. Later he received the court title Kawachi Daijo, signing Hizen no Kuni Kawachi Daijo Fujiwara Masahiro. Of the date the published record is candid: although tradition gives Kan'ei 5, works dated as late as Kan'ei 16 still sign only Hizen no Kuni Saga-ju Masahiro, and the title first appears on blades dated the eighth month of Kan'ei 18, so the modern view places the appointment about that year. Among the waki-Hizen, the branch smiths working outside the main Tadayoshi house, the NBTHK holds him the most accomplished of all, 「傍肥前の中でも最も技量が優れており」[[c:1]].
What distinguishes him is exactly what sets him against the main line. Where the Hizen house is read first in its calm, deep-nioi chu-suguha, Masahiro favored the opposite, and the published sources state it plainly: 「作風は乱れた刃を好んで焼き」[[c:2]], his hand favored the irregular temper. His characteristic hamon begins with a suguha yakidashi at the koshimoto and rises into a choji-dominant midare, mixing gunome, gunome-choji and large gunome with ko-notare and at times a togari or angular flavor. The clove pattern the judges liken to that of Musashi no Daijo Tadahiro. The temper is set high and low, in places linking clusters of midare with a quieter suguha-toned line, long ashi and yo entering well; the nioiguchi is deep, with thick ko-nie gathering in the valleys of the midare, a little tobiyaki and at times muneyaki, sunagashi running well and long kinsuji appearing. On one such katana the published sources write that he forges the midareba he excelled in and shows his true ability to full effect.
Beneath that flamboyant edge lies the refined steel he shares with the rest of the school. The jigane is a tightly packed ko-itame becoming the Hizen komenuka-hada, the rice-bran skin: a dense ji with dust-fine ji-nie laid thickly and fine chikei entering well, bright and clear. The boshi runs straight to a ko-maru with hakikake and a long, deep turnback, at times opening into a small midare-komi on the omote. The sugata is the well-balanced Hizen shape, at times wide in body with an extended or large kissaki, powerful and forceful. The nioiguchi stays bright over both his showy and his quiet work, the constant of his ji and ha.
He was not, however, a smith of one manner only. A clear register of his record is the chu-suguha he also commanded, a quiet suguha toned with a shallow notare and mixing ko-gunome, ko-ashi and yo entering, fine kinsuji and sunagashi naturally interwoven, the nioiguchi bright over the same well-packed ko-itame jigane. One Juyo katana of Kan'ei 11, worked in this calmer manner, the published sources name his finest, 「この刀はその白眉である」[[c:3]]. His dated works survive only in small number, running from Kan'ei into Kanbun, and several Juyo pieces whose signatures blend his pre-title and post-title styles are valued for fixing the chronology of his career; he is said to have died at fifty-nine in Kanbun 5 (1665).
His distinction from the main house is drawn by the judges themselves. He is set apart not only by his preference for midareba over suguha but by his sujikai yasurime, which differ from the main line's, and by his consistent practice of signing katana on the sashi-ura. The published sources read his blades as carrying a more natural vigor and driving spirit than the main Tadayoshi house, 「本家忠吉家の作よりも自然, 覇気のある作が多く」[[c:4]], and one entry says of a representative piece that he forges the midareba at which he excelled and displays his true ability without reserve, 「彼が得意とした乱れ刃を焼いて, その本領を遺憾なく発揮している」[[c:5]]. He stands, then, as the most gifted of the Hizen branch hands, the one among the waki-Hizen whose work most readily approaches the main line in quality while keeping a manner distinctly his own.
For the collector Masahiro is a desirable and attainable Hizen name. Fujishiro grades him Jo-jo saku. He has no National Treasures and no Important Cultural Properties; his record runs instead through the Juyo rank, where some thirty of his blades have been designated, the published sources calling his finest powerful and forceful in both ji and ha and richly animated. Documentary interest is high among them: one Juyo wakizashi carries within a koshi-hi a relief of Shigetsu Hotei by the carver Yoshinaga, a design the published sources call extremely rare among Hizen blades and of notable value for the study of the province's carving. Provenance is only partly recorded, so it is best stated quietly: his blades are held in private collections of recorded whereabouts rather than in a roll of famous houses. A signed Masahiro is not beyond the reach of a serious collector as a top main-line Hizen blade can be, and from time to time, with patience, one of his Juyo works comes to light, a chance to hold the flamboyant midareba of the most accomplished of the waki-Hizen.
