The Oei- and Eikyo- smiths represent the resurgence of the school in Province during the early period, an era in which a conscious revival of -period aesthetics transformed the character of swordmaking after the bold, expansive forms of the period. The school's foremost representatives are Yasumitsu and Morimitsu, described by the as the "twin pillars" of Oei-, both active around the Oei era (1394--1428). Morimitsu is held by one tradition to have been the son of Moromitsu, a representative smith of the late group, and his earliest dated works bridge the transitional character of his father's generation and the fully developed Oei- idiom. The name Yasumitsu was successively inherited through as many as five generations, while the succeeding Eikyo- phase -- centered on the fourth-generation Norimitsu and his contemporary Sukemitsu -- carried the tradition forward into the mid- period. Related smiths such as Tsuneie of the branch worked in a manner so closely aligned with production that the observes there are "no grounds -- whether in workmanship, the character of the signature, or any other point" by which their work could be distinguished from the main line.
Within the Oei- manner, two principal modes of tempering are recognized. The first is a brilliant -ba in which open, relaxed with -- widely opened bases -- is mixed with , forming what the describes as "a splendid, large-patterned, flamboyant ." The second is a calm of restrained, archaic tone that can, at first glance, "call to mind the workmanship of the -period school or earlier traditions." In both modes the school's identity is revealed through shared forging characteristics: mixed with in which the grain stands out conspicuously, with dark lines resembling entering the and or standing prominently in the ground. The characteristically incorporates with widely opened hips, and entering well, the temper -dominant with and a that is "bright and clear." The assumes the idiosyncratic form popularly termed the "candlewick" (rosoku no ), becoming pointed at the tip -- a diagnostic hallmark of the school. A further point of connoisseurship is the finishing of with rounded ends () above the . The transition from Oei- to Eikyo- is marked by Norimitsu's development of a somewhat intermediary character, retaining the and bright of the earlier masters while introducing tighter grain and elements that point toward the eventual style. Moromitsu's earlier production establishes the bridge from the opposite direction, his period works showing "signs foreshadowing the style of Oei-" in their more flamboyant passages.
The ideal pursued by the Oei- and Eikyo- smiths "appears to have been a revival of the period," visible in their elegant proportions and in the deliberate re-creation of tempering that had fallen out of favour during the period. Yet the consistently emphasizes that the school's own distinctive character is always discernible beneath this revivalist surface. Yasumitsu's production spans every format -- , , , , and the exceedingly rare omi- -- and he is praised for leaving behind "highly skilled works in every format." Morimitsu's finest preserve their original with imposing, deeply curved forms that convey the grandeur of an earlier age, while the vigorous internal activities within the tempered edge bring forth his strengths "without reserve." Both masters' works are consistently described as -- sound and well-preserved -- with a of superior quality possessing an richness. The school's influence pervaded early sword production, and the Eikyo- continuation through Norimitsu ensured that the tradition maintained vitality and refinement well into the fifteenth century. Whether in the commanding vigour of the large-pattern or in the quiet classical elegance of the mode, the Oei- and Eikyo- smiths collectively represent one of the most accomplished chapters in the long history of swordsmithing.