Hiroyuki (左弘行) was a swordsmith of Province belonging to the school, which emerged in the early period. Breaking away from the classical style formerly characteristic of Kyushu works, the lineage established a refined manner in which both and appear bright and clear. Hiroyuki is traditionally said to have been the son of Yukihiro, and is regarded as a smith active around the Shohei era in the mid period. Within the group, smiths such as Yasuyoshi, Yukihiro, Yoshisada, Kunihiro, Hiroyuki, Hiroyasu, and Sadayoshi faithfully inherited their master's manner and the school flourished greatly. Few signed works by Hiroyuki survive, and the great majority of blades bearing his attribution are and , their authorship determined through careful appraisal of workmanship and style rather than inscription.
Hiroyuki's works display the bold, imposing characteristic of the mid period: wide with little difference between base and tip widths, shallow , and , presenting a grand and powerful silhouette. The is typically mixed with and , with the grain tending to stand; thick adheres and enters well, while the steel often shows a somewhat darkish tone with a slightly whitish tendency. The is characteristically based on or shallow , into which are interwoven , , , and ; the is deep with thick that may include patches of somewhat coarse producing an uneven effect. Throughout the tempered area, conspicuous and run vigorously, and the frequently shows a tendency. The typically enters with a slightly pointed tendency at the tip and displays vigorous . A faint may also be observed. Compared to other smiths, Hiroyuki's tempering tends toward a relatively restrained irregularity in which the rises and falls of the do not stand out strongly, at times showing a manner that serves as a distinguishing point of attribution.
Hiroyuki's surviving body of work demonstrates a consistently high standard of craftsmanship within the tradition. His blades are praised for their condition in both and , their generous , and the abundance of internal activity within the tempered area. The manner in which thick adheres shows varied change, and the interplay of , , and occasional creates a richly animated hardened edge. The large-scale is consistently described as dignified, robust, and brimming with spirit. Among the group's later generation, Hiroyuki stands as one of the most accomplished successors, faithfully carrying forward the bright, clear aesthetic that defined the school while expressing a distinctive personal idiom through his comparatively quiet yet powerfully conceived tempering style.