Masayuki is the early signature of Yamaura Naizōsuke Tamaki, the smith who in Kōka 3 took the name Kiyomaro and came to be called the Yotsuya Masamune, the foremost master of the . The published sources put the identity beyond doubt: of one Tenpō 11 they write that "Yamaura Masayuki is, needless to say, the later Hara Kiyomaro", and of another that "Minamoto Masayuki is the signature Kiyomaro used before Kōka 3". He was born in Bunka 10 as the second son of the gōshi Yamaura Nobukaze of Akaiwa village in Komoro, Shinshū, studied forging first with his elder brother Saneo under the Ueda-domain smith Kawamura Toshitaka, and went to in Tenpō 5 under the patronage of the bakufu military scholar Kubota Seion. Looking past the and Kotetsu copying of his contemporaries, he reached back to the masters and perfected himself in their transmission, the manner above all. The blades of this group belong entirely to that Masayuki period, before the change of name.
The hand is read in the temper. Over the body of his work runs a , and into it he sets a pointed -ba, the angular accent that distinguishes him where the bare shared with every smith does not. With it go a and , entering long, the deep and attaching, the in places coarse and gathering, with and on his most vigorous pieces. Through the temper run long and frequent , the conspicuous activity of his -aimed , present on most of the corpus and singled out by the published record as remarkable even on the smaller blades. The is clear, at times somewhat blurred, the line restless rather than composed. The answers the edge: , thrusting up pointed with , now and then a small round.
The is worked in the manner. He forges an that flows, and in a good third of his blades it tends openly to , the make the published sources tie directly to his study of the transmission. lies over it and enter frequently, the grain standing a little; on the tighter pieces it draws into a . There is no , for this is a hand reaching back to rather than a one, and the absence is itself part of the reading. The construction is imposing: the wide or standard in body, the high or running toward the point, the extended or a full , several made in , the withered for a keen impression.
Within the one Masayuki period the work falls into two registers. The first is the imposing - , signed in the long forms Yamaura Tamaki Masayuki and Yamaura Tamaki Gen Masayuki, on which he carves twin grooves or at the base; of a Tenpō 11 example made at twenty-eight the published sources say it "is filled with commanding spirit", the vigorous construction one of his particular strengths. The second is the smaller-scale work, the and , a tighter under a small with , cut with a thick-chisel two-character and, on one rare blade, a cutting-test inscription; the published commentary notes that in these years his manner of signing was not yet fixed, with unusual character forms and varied file marks on the tang. A Tenpō 11 subdued in impression is still called a masterpiece in the -.
What sets the work apart is the very thing the judges name. His is the aim worked out in Shinshū and on the road, the flowing -leaning and the pointed in a -laden , with the long and of a hand reaching for Saburō, set against the and Kotetsu imitation of the smiths around him. The published sources call Kiyomaro the foremost smith of the , displaying technique in both and that surpasses others, and read even these early blades as already directed at the upper reaches. He is the open record of how that mastery was reached: the apprenticeship, the flight, the Nagato-uchi years at and the Komoro castle work, all documented in the signatures themselves.
For the collector he is a signed and fully knowable name from a short, dramatic life. The works on record run across , , , and , nineteen of them in the tier and all signed; he has no National Treasures and no Important Cultural Properties, his standing carried instead by that body and by the documentary weight of the Masayuki signatures. The provenance is sparse but apt: one blade descends from Kubota Kiyone, the patron under whom he learned at . One , presented to the -domain retainer Seigai Fukuda, the published sources call "a work executed to the maker's full satisfaction", and one carries the uncommon cutting-test inscription Tata Dōdanbarai. Because none of these can ever leave the designated tiers freely, a signed Yamaura Masayuki reaches the market only seldom and at the top of it; a privately held example is a notable thing for a collector to encounter, a document of the early hand of the man who would become the Yotsuya Masamune.