(古備前) is the oldest stratum of the tradition, the work of the smiths who forged in province from the late period, around the Eien era, into the early and middle . The published sources trace the line to a founding Tomonari and to Masatsune, the two counted from old as the twin pillars (sōheki) of the group, and they are careful to read each of the great names as a name-line rather than a single man: surviving signed Tomonari carry Katei-era dates of the early , the Masatsune name is transmitted across three generations or more, and the Kanehira and Sukehira signatures fall into distinct chisel hands. Beside the pillars stand the three Sanpei, Kanehira, Sukehira and Takahira, and a wider field of hands, Nobufusa, Naritaka, Yukihide, Sukekane, Yoshikane and the smiths of the Masatsune house such as Tsunemitsu, Toshitsune and Tochika. From this root, before the school's great flowering at Fukuoka, the whole tradition descends. Several of these names recur in the early line of the province, so that the appraisal of any one of them begins by separating the archaic hand from its later namesake.
The shared vocabulary is consistent enough that the school is read as a single manner held across many hands. The is the slender of the age: with , high with pronounced , the curvature settling toward a small . The forging is an mixed with , the grain often standing a little (), with adhering, woven through, and over it the speckled or a of old steel. The temper is the quietest reading of : a tone undulating shallowly into , into which and enter, adhering thickly, and working in the , and and running through; the runs straight to a calm , at times to with , and a dropped above the is an archaic touch met across the group. Within that norm the early masters keep their individuality. The sources separate Tomonari and Masatsune by saying the first is marked by the excellence of his and the second by the excellence of his ; Yoshikane is known by a that stands more than his fellows and a that sinks; Yukihide leans his in the reverse () direction; Naritaka crowds the edge with and a doubled ; and Kageyasu sets angular and further forward than the pillars, the manner the earliest would inherit.
A collector seeks as the source of the line, and the turns on restraint rather than display. Against the later Fukuoka , whose flamboyant stand under a brilliant , keeps its quiet and its archaic; against the line of Nagamitsu, which is -based and -bearing, the edge is -, a distinction the published record makes the whole ground for separating Junkei from the man he was long mistaken for. The standing of the best members is fixed by the weight of designation behind their names: Tomonari, Masatsune, Kanehira and Nobufusa are graded Sai-jo by Fujishiro, and the school's summit is the Ō-Kanehira, the broadest and most powerful old produced, a National Treasure long held as the patrimony of the Ikeda house and now in the Tokyo National Museum. The signature works carry provenance through the first houses of the realm, the Imperial Household, the Tokugawa shogunal family, and the Ikeda, Maeda, Date, Shimazu and Satake , with the Nobufusa given by Ieyasu to Sakai Tadatsugu and the Naritaka blade transmitted as the wearing sword of Nasu no Yoichi. Because so much of the corpus is held as heritage and the signed early hands are scarce, a signed reaching open hands is among the rarer encounters the field affords, a document of how the tradition began.