Hayashi Matashichi (林又七), also known as Seizaburō Shigeharu, was born in Kumamoto in Keichō 18 (1613) and is regarded as the founder of the Hayashi lineage among metalworkers ( Hayashi-). His forebears were gunsmiths () of Owari Province who, it is said, also occasionally made . In his father Seibei's generation the family served Katō Kiyomasa as gunsmiths and relocated to Kumamoto; after the Katō house was dispossessed, they entered the service of the Hosokawa, who were transferred to that domain. Matashichi died in Genroku 12 (1699) at the age of eighty-seven. As head of the Hayashi school, he is a master craftsman who "occupies the highest rank among artisans." The Kinkōroku records that metalwork flourished under the guidance of Hosokawa Sansai Tadaoki, and the four principal lineages — Hayashi (Kasuga), Hirata, Nishigaki, and Shimizu — trace their origins to that patronage. Incorporating the strengths of Owari and early Shōami work (ko-Shōami), Matashichi devised distinctive approaches to and inlaid carving (horikomi-), thereby establishing himself as the progenitor of a distinct school.
Matashichi's hallmark is his exceptionally well-forged iron plate, whose lustrous, viscous surface is likened to the color of yōkan — a deep, richly glossy tone that the Kinkōroku praises in memorable terms: "the color of the iron is without equal; the forging is tightly knit, and its beauty is beyond comparison." The repeatedly return to the dense, clinging sheen of this iron as the principal point of appreciation. Beyond the iron itself, Matashichi commands a wide repertoire of technique. His gold is applied with deliberate passages rendered "as though broken or torn," conveying what the call "the exceptional refinement of Matashichi's aesthetic sensibility." His kareki- (withered-tree inlay) is especially the artist's forte, "reaching a level that other craftsmen found difficult to match." His (ground openwork) — whether rendering bamboo, paulownia, distant pine, or cherry blossoms at Yoshinogawa — demonstrates an outstanding sense of design; later generations actively copied these compositions across multiple schools, yet "in terms of the quality of the iron, the excellence of the overall bearing, and the refined elegance," none surpass Matashichi. He also produced in which the and employ differing base metals, a practice noted as distinctive to his hand.
The evaluative language across decades of is remarkably consistent: Matashichi's works possess a "dignified, firmly-set presence" and a "tenacious quality" in the iron; they are "high in tone and elegance," recalling the saying that his work made even other craftsmen "keep their distance by three sha," so elevated was its authority. His openwork is praised for its bold, unhurried spaciousness, its economical -oki (placement of relief), and its capacity to convey poetic feeling — "the springy resilience of bamboo," "a fresh breeze stirring through each leaf," or the crystallization of the bushidō ethos in the form of a . Among his oeuvre, the distinguish two constructional manners — pieces of keen, sensitive construction with little flat , and others of broad, generous construction with fuller — both developing "splendidly distinctive manners of workmanship." Whether signed with the precious "又七" or appraised as , Matashichi's are recognized as expressing "the appeal of to the fullest extent."