Masanori signed his work in full as Yamato Daijo Fujiwara Masanori, and the earliest of his dated blades carries the year Keicho 13 (1608), with later pieces reaching Genna 2 (1616), 'ei 1 (1624) and Keian 4 (1651). That span sets him squarely in the first generation of smiths working at Fukui in the opening decades of the period, active alongside the first and second generations of Yasutsugu. The published sources transmit, as one view only, that he descended from Yoshinori of Yamashiro, that his native province was Miyazu in Tango, and that he afterward moved to Fukui in . They place him in the immediate orbit of Yasutsugu, perhaps as a pupil, and add that even where that cannot be shown it is difficult to deny that he came under that smith's influence. The name continued through several more generations after him, but it is this first Masanori, with his long signature and his , whose hand the four designated blades record.
His everyday manner is read first off the . Over an that flows and stands a little (板目 on all four blades, on three, with flowing grain entering on two) he lays , and on the larger (地景) appears; the steel is sometimes blackish. The that runs above it is a built from , large , pointed and -like (矢筈) heads, with attaching, the running to a small round turnback. What the published sources return to, however, is not any single feature of the line but the character of the : it tends to sink, somewhat subdued, and they sum the whole up by saying that his is a subdued- blade generally close to the Seki smiths, 「匂口の沈んだ刃で、一般に関物に近い」. That sinking quality, paired with the flowing standing , is the closest thing he has to a constant tell across the busier work.
Not every blade is busy. On one of the the hand quiets entirely: the is a fine with only a slight tendency to stand, appearing, and the settles into a (直刃) with and , the straight to a . The published sources name this alongside the as the other thing he often produces, and they judge the piece refined in its forging, with the and well ordered throughout, 「地鉄が精美で地刃の出来がよく整った」. It is the disciplined counterpart to the flowing manner, and it shows that his training carried a calmer register as readily as the showier one.
The ceiling of his work lies elsewhere again. His seventh-session designated , the oldest of the four on record, is the height of his ambition: a wide blade running to a large point, cut on the in single-bevel construction (片切刃) and on the in , modeled after the so-called -Sadamune (切刃貞宗). Above a standing with frequent runs a paired so- in a large (双文大乱) mixed with , and entering freely, running through, and the passing into full tempering (皆焼), the thrusting up with and . A (三鈷剣) is carved on the . Of this blade the published sources write that the workmanship is excellent, very nearly reaching the first-generation Yasutsugu, and that among Masanori's own works there is none to set beside it, 「殆んど初代康継に迫るものがあり、同作中これに比すべきものがない」. The construction is itself a recurring trait of his record rather than a one-off, appearing on a as well, but it is on this that the Sadamune model is named and the ambition fully realized.
What distinguishes Masanori within the crowded field of is best drawn from his own grounded features rather than by contrast with his neighbors. The flowing, standing and the sinking are the marks the published sources tie to his closeness to the Seki tradition, and they are what hold his everyday work together; against them, the blades and the Sadamune-modeled showpiece are the reach toward an older and grander manner. The judges note on the twenty-third-session that his own characteristic features show densely in the and of that piece, 「地刃に正則の特色が濃く」, and on the blade that the carving is splendid besides. He is, in the school's reckoning, a smith whose typical work sits close to Seki yet who could, on his best day, turn out a that approached the founder of his own province's tradition.
Masanori's designated record stands at four blades, two and two , every one signed in full and on an ; his record reaches the tier and no higher, and none of the four carries a recorded line of provenance or a named owner. The seventh-session , the Sadamune-modeled piece the published sources rank without equal in his output, is the work by which he is best known, and the two , one quiet in and one densely his own, round out a small but coherent body. For the collector this is a smith whose work surfaces only occasionally and whose finest blade is a landmark when it appears; the signed and of his hand are not beyond reach in the way a designated cultural property would be, but they come to market rarely, and a piece in which his subdued and flowing standing are clearly present rewards patience more than it does pursuit.