Yoshihiro, commonly known as Go, resided at Matsukura-go in Province and is celebrated as one of the foremost members of the Masamune Juttetsu, the Ten Great Disciples of Masamune. His appellation derives from the place-name Matsukura-go, abbreviated to "Go" and, from the Keicho era onward, written with the character E (江) owing to its phonetic equivalence. References in the Oseki-sho, a -period compilation of tang-rubbing drawings, record a single-character signature reading E alongside the notation "E Umanojo," suggesting a possible connection to the Oe clan. As with Sadamune, no extant works bearing an authentic chiseled signature by Yoshihiro are known; all attributions rest upon connoisseurship appraisal. His period of activity spans from the very end of the period into the opening years of the era, and numerous blades attributed to him appear among the celebrated swords recorded in the Kyoho-era -cho, including such renowned pieces as the Inaba-Go, Tomita-Go, Nakagawa-Go, and -giri-Go.
Yoshihiro's forging within the - tradition is distinguished by a refined restraint that sets his work apart from that of Masamune and Norishige. His is characteristically a well-packed , frequently mixed with and exhibiting a tendency toward or a -inclined texture. Extremely fine adheres thickly across the surface, and delicate appear with notable frequency, producing a steel of exceptional clarity described repeatedly in official designations as -- bright and luminous. The is typically founded upon a gentle mixed with and, in certain works, -flavored elements. The is consistently deep, with thick, evenly distributed from which , , and occasional emerge. While these activities are present, they manifest with greater composure than in the work of his teacher or fellow pupils; the defining quality is instead the vigorous action of within the tempered edge, which imparts to both and a brilliance and clarity that stands a perceptible degree above even the finest work. The constitutes a cardinal hallmark: tempered deeply and richly covered in , it assumes an -like character, often finishing with or at the tip.
Yoshihiro occupies a singular position within the school as the smith whose work achieves the highest degree of luminous refinement. The Meizukushi Hiden-sho observes that his tang shapes generally resemble those of Masamune and Sadamune, underscoring his intimate connection to the mainline lineage. Alongside of , he was regarded as forming a "matched pair" of peerless masters among Masamune's pupils. Many of his attributed works carry distinguished provenance through houses -- the Uwajima Date, Ikeda, Owari Tokugawa, and Fukui Matsudaira families among them -- and bear gold-inlay authentications or appraisal documents by successive generations of the house. That so many blades attributed to Yoshihiro have attained the highest levels of official recognition, despite the complete absence of signed examples, testifies to the consistency and unmistakable individuality of his aesthetic: a poised synthesis of vigor and crystalline clarity that remains, across centuries of critical appraisal, immediately recognizable and profoundly admired.