Centered at Fukuoka in across the middle decades, this window is the loud heart of the school, the moment when the -mark workshops pushed their tempering to its showiest extreme. The repeatedly name the triad as its representative hands: Norifusa, Sukezane, and Yoshifusa, a grouping cited again and again as the smiths who forged the most flamboyant of the period. Around them work Sukefusa, recorded as a two-character-signature smith from whom Yoshifusa, Norifusa, and Sukezane are transmitted as sons, together with Sukemori, Sukehide, Hirotoshi, Narichika, and a Fukuoka Yoshiie whose two-character blades are at times hard to separate from the line. Norifusa, son of Sukefusa, later relocated to a place called Katayama and so came to be styled Katayama , a branch reading often left an open question between and a Katayama near Fukuoka itself. Where the earlier Ko- generations still carried a character, with more prominent than , this phase resolves that older quietness into full, deliberate spectacle as rose to supply the warrior demand.
The defining temper here is worked at large scale: , layered , and tadpole-shaped that climb and drop in tall waists across the . The blades named Norifusa show wide , high deep , retained , and a generous , the broad mid- that carries such a busy temper. The ground is a well-packed , sometimes standing into with mixed , carrying densely applied , fine , and a vivid that rises clearly against the steel; the reads bright and clear. and enter in profusion, the runs soft and -dominant with , and and play through the hardening. This separates the phase on both sides. Against the calmer Ko- , the Fukuoka work is taller and more exuberant; against the later Yoshioka , whose temper narrows into smaller-motif with conspicuous and a frequent lean, the Fukuoka temper is broader, deeper, and less regular. The Katayama-attributed blades within this phase already foreshadow that reverse tendency, hardening flamboyant but reverse-inclined .
For , the combination to read is wide mid- , large undulating with jūka and mixed in, a soft -dominant , and standing over bright . Two-character signatures cut boldly with a thick chisel recur across Norifusa, Sukemori, Sukehide, and Norinawa, and many surviving blades are or . The named masters carry weight beyond style: a Narichika descends through the Date family of Sendai, a Norifusa passed through the Yanagisawa family, and appraisals by Kōtsune and Kōchū accompany Sukemori and Norifusa works. One Norifusa bears a reading Tenka Daiichi, "Best Under Heaven," a measure of how the connoisseurs of later centuries ranked this Fukuoka peak among production.