The earliest dated work that survives under Sukemitsu of is a of Eikyo 9 (1437), an , signed blade that displays the manner the published sources call Oei-, and which they pronounce an imposing, dignified piece (堂々としたものである). The latest is a of Kansho 3 (1462) that carries within its signature the common name and title Rokurozaemon no Jo. Between those two dates lies a span of twenty-five years and a stylistic crossing, for Sukemitsu worked the moment the published record names the move from Oei- into . The lists seven smiths who signed this name, and the , judging from the year inscriptions, reads the dated works gathered here as the among them, the head of the family who fathered the brothers Ukyo no Katsumitsu and Sakyo no Jo Munemitsu. His blades stand at the hinge of that descent, the Oei- manner of the early fifteenth century already turning toward the workmanship his sons would lead.
The matter that distinguishes his work is a , a whose valleys open wide at the waist, mixed with a little and built into a varied . It is -dominant with attaching, fine and running within, the at its best bright. On the early Eikyo the temper opens at the waist with pointed elements mixed in, slight and laid over it, and the runs straight with to a pointed tip. On the mature dated pieces the waist-open takes in -ba and angular teeth, in places reminiscent of , the whole still -dominant with and bright in the . The descent of his date is read off the temper itself: of the Kakitsu 3 (1443) the published sources note that the amplitude of the is small and the inconspicuous (乱れの振幅が小さく丁子が目立たない), and in that quieting of the once-flamboyant Oei- clove pattern they read the period coming down. The waist-open temper is his constant, and its narrowing waves are his clock.
Beneath the lies an mixed with , the grain standing in places, over which a clear rises, the bar-shaped reflection of the steel. The attaches somewhat thickly and enter well; on the broader the grows fine and dustlike, a faint drifting above it. The answers the temper, turning in to a on the agitated blades, running straight to a small round turnback or pointing and returning on the quieter ones. The moves with his dates and forms: the early slender with deep and a in the Oei- stance, the mature of standard width with a noticeable taper and a thick , the and broad pieces, elongated and thick. The carvings are a recurring pleasure of his work, a grass-script and and a sutra text on one blade, twin grooves on another, and on a Bun'an 6 (1449) the incised deity name Ichinomiya Daimyojin. The published sources call that a piece in which Sukemitsu's working range is clearly shown (祐光の作域がよく示されている).
The generations are the open question of his name, and the published sources resolve it by date. They observe that several generations of Sukemitsu have been pointed out and that the lists seven of the name, an earlier small-curvature Sukemitsu of around the Eiwa era among them; the dated blades, on the evidence of their year inscriptions, they assign to the first generation. His fatherhood of Katsumitsu and Munemitsu is fixed by a document blade outside the corpus, a Bunmei 9 of Munemitsu inscribed as the work of Sukemitsu's second son, Sakyo no Jo Munemitsu, which the judges say clearly demonstrates the transitional workmanship as moved from Oei- into (応永備前から末備前へ移る過渡期の作風). His own dated pieces show that hand mid-transition, the Eikyo imposing and Oei- in flavor, the later and calmer in their , the construction and the -and- still carrying an Oei- character while the recedes and the waves narrow. The blades signed with the full Rokurozaemon no Jo title, of which the published sources say extant examples are extremely few (現存するものは頗る少), are the ones they treat as the touchstone of the .
Within the school he belongs to the main line at its mid- turn, the generation between the Oei- of Morimitsu and Yasumitsu and the dense workshop his sons would run. His distinction is read not by borrowing a comparison but by his own grounded traits, the waist-open with its subdued , the over a standing , the bright and the pointed and angular teeth that mark the direction of his hand rather than the round clove of the older . The published sources value his blades as material as much as as swords: a signed as made at Takehara in Settsu records the documented movement of smiths to other provinces in this period and is called valuable source material for the study of the late- smiths (末備前鍛冶研究の好資料). Through Katsumitsu and Munemitsu his line became the principal workshop of the late , the names that would lead the school into the mass production of the Eisho and Tenmon eras.
Fujishiro's rating is not recorded for him, and his designation record is modest in scale: seven works on record, all at the level, with a further blade preserved in the Imperial collection, and none of the higher tiers among them. That Imperial blade descends in the Imperial Family and is held today in the Hayashibara Museum of Art, the one clear provenance to survive in his data. The blades are a body of mid- , and held in private and long-recorded hands, and one of recorded whereabouts appears from time to time rather than rarely, a more findable thing than a though not on that account common. The value of his work is partly documentary, for the dated, signed, pieces let the Oei- to crossing be worked out blade by blade. A Bun'an 5 (1448) bears on the a gold-inlaid cutting-test inscription by the celebrated tester Yamano Kaemon-no-jo Nagahisa, evidence that his swords were proven as cutters generations after they left his forge. For a collector the Rokurozaemon no Jo Sukemitsu is the dated, knowable end of the name at its transition, a sword on which the period arc and the family question can be read in the hand, and on the best of which the working range of the smith is fully shown.