Following Sadamune, the two smiths who emerged in in the period were Hiromitsu and Akihiro; nearly every commentary on his blades opens with that sentence. A disposition toward can already be found, though rarely, in Sadamune, where it amounts to no more than an artless prominence of ; with Hiromitsu and Akihiro the sources see "the completion of the full-fledged ", an invention that influenced the later smiths and swordsmiths of other provinces alike. The two "developed an innovative and lively style". Hiromitsu stands in the mainline descending from Kunimitsu, after Masamune and Sadamune; the genealogies divide between the two schools, and the prevailing reading assigns a first generation to Masamune's circle and a second, the master of the Bunna through Joji years, to Sadamune's.
Nearly everything that survives under his name is the and of the Enbun and Joji type, wide in , thin in and shallow in ; reliably signed are exceedingly rare. He tempers a fronted by and mixed with ; within it appears his round-headed clove, the dango-choji (団子丁子), the form the published sources single out as his individuality. , and spill across the until the whole blade is fired as . lies thick, and run through the , and the is bright and clear. The enters as , rising to a point or breaking into a flame-like form, and returns deeply, often burning down the . An Enbun 5 (1360) of the Ikeda line is called "typical and outstanding", its individuality read in the dango-choji.
The beneath this temper is , tending overall to stand, with thick and frequent , at times mixed with . Of a Bunna 5 (1356) the sources write that the activity within the and the character of the carry "an atmosphere recalling Masamune in a single thread". In places an exceptionally bright breaks down into the , and the often widens toward the upper half until the temper fills the whole surface.
His dated work opens with Kanno (1350) and runs through Bunna, Enbun, Koan and Joji. Akihiro's dates begin only at Enbun and continue past him into , Eiwa, Koryaku, Shitoku and Meitoku, eras never seen on Hiromitsu, so his seniority is held certain. He cuts the long no junin Hiromitsu with the date written out in full, and the published record is categorical that he never signs ju (相州住), Akihiro's form. A rare two-character stands beside it, undated and more angular in its chiselling; the Seikado Bunko, the Nezu Museum and the Kurokawa Institute each preserve one, with pieces of quality among them, and Honma left the generational question open, asking whether "the two-character signature might be the first generation and the long signature the second". A quieter register also runs beside the flamboyant standard. The Bunna 2 (1353) of the Matsudaira line, the sole surviving example of his title Saemon-no-jo, shows a wholly small in pattern with few and and inconspicuous ; the sources describe "a calm " imparting "a somewhat archaic feeling", and a stands out in its .
The discriminators against Akihiro are concrete. The signature rule is one; the build is another, for Akihiro's more often runs smaller, read as the chronological transition of shapes, while a Joji 3 (1364) of the Kishu Tokugawa line is described as "larger even than usual, with real presence". The dango-choji is the third. Against the contemporaneous of the Kyoto smiths the line is structural: his favored temper "differs from the Kyoto Hasebe school in that forms its main body", where Hasebe Kunishige and Kuninobu work theirs over a base of small . In terms, the sources note, he is an exact contemporary of the so-called Enbun Kanemitsu.
Fujishiro grades him Sai-jo . Forty-five designated works are on record: two Important Cultural Properties, nine , twenty-three and twelve Important Art Object certifications, the tiers in part overlapping, for the Saemon-no-jo and an Enbun 3 , its stolen inscriptions restored as , both later advanced to . Signed pieces dominate, thirty-three against ten unsigned, nearly all dated, anchoring his chronology era by era. Three named blades stand in the record: the Okurikara Hiromitsu of the Date family; the Kikkawa family blade styled "Furiwakegami Masamune" since the period, re-judged to Hiromitsu at its certification; and the Uesugi house styled Kashagiri (火車切). His provenance runs through the houses, the Kishu Tokugawa, the Matsudaira of Fukui, the Ikeda, the Satake, the Nanbu, the Date and the Uesugi, with the Mitsui among the modern collectors. The two Important Cultural Properties are patrimony, and several of the finest remaining pieces rest in the Nezu Museum, the Seikado Bunko, the Sano Art Museum and the Kurokawa Institute. What a private collector may realistically encounter is the Tokuju and tier, thirty-two blades of partially recorded whereabouts, most of them held rather than traded; a signed and dated Hiromitsu comes to market only rarely, and when one does it is among the few chances the field offers at the perfected of .