A designated at the 20th session in 1971 sets out what this body of work is: an blade, somewhat slender, with high and marked , and on its tang nothing but the single character (一). The published sources explain the name from that mark. In there are blades with the one character cut on the tang, and "such works have broadly been termed the group". Within the lineage they distinguish the Fukuoka , flourishing from the early through the late period, from the Katayama and Yoshioka branches of the mid- onward and the Iwato group active into the period. Of that first they conclude that, though it shows a slight fatigue, "it is a work that does not descend later than the mid- period". Seven designated works on record carry this bare signature, and the published commentary notes that an may be the 一 alone, the 一 above a personal name, or a personal name alone. Because these blades carry only the character, the individual smith cannot be fixed, and the attribution rests on period, school and the manner of the inscription; the blades of mid- date are placed in the Fukuoka .
The temper is a . On the 1971 the published sources describe a flamboyant into which , small and somewhat pointed elements are mixed, with a slight tendency, and abundant and adhering. An designated in 1989 is said to "exhibit a brilliant, highly changeful ", worked in . On the shortened examples the same pattern reads deeper: a with a little mixed in, and , the deep and in places subdued. The runs straight to a small round return (), on one slightly irregular before turning back shallowly.
The forging is , on two of the showing an overall tendency to and on the first standing slightly, with noted on the 1989 . A stands in the of each of the four blades that have a full published description, faintly on that and distinctly on the others. On a slightly shortened designated in 1982 the published sources call the work mid- Fukuoka , with a deep- inclined to , and entering well, and "a clearly appearing in the ". The three Important Cultural Property plates record only form, forging, temper and length, and say nothing of the reflection.
The works divide into blades kept in original form and blades shortened but still bearing the character. The pieces show the fuller, more varied temper, and of the 1989 the published sources write that it "fully demonstrates the distinctive features of the school, and the workmanship is good". The shortened of 1974, its mixed with a little , is judged an orderly, well-balanced work and appraised as Fukuoka from the style of its inscription as well. Two of the blades are , and here the published sources leave a question open: are numerous in the period and seen above all in and Yamashiro, but "what kinds of people wore them and for what purposes" is a matter they set aside for further research. The corpus also holds a , the one example of that form.
The judgments return to the same pairing. A deep- with and is set over an carrying a distinct , on a with and . These are the features the published sources name when they place a bare 一 blade in the Fukuoka , and they place the slightly shortened of 1982 at mid-.
Three of the seven are Important Cultural Properties held at shrines: a at Itsukushima Shrine in Hiroshima, 87.6 cm long, in with a ; a at Takeda Shrine in Yamanashi, 64.2 cm long, of the same forging and temper; and a at Tanzan Shrine in Nara, in with a , its temper recorded as . They are patrimony kept in the shrines' care. The other four are blades, of which one, of recorded whereabouts, is in private hands. There are no National Treasures among the works under this signature, and none at the level. A blade signed only 一 appears on the market seldom, and a privately held example is a rare thing for a collector of early to encounter.