The school was founded in Kyoto during the Eiroku era (1558--1570) when the Seki smith Kanemichi relocated from Province together with his four sons: Iga no Kami Kinmichi, Kinmichi, Tanba no Kami Yoshimichi, and no Kami Masatoshi. Collectively celebrated as the -ikka (Three Distinguished Products family), the brothers greatly enhanced the reputation of the group that would become one of the two dominant smithing lineages in Kyoto during the and early periods. From this founding nucleus, the school's branches multiplied: the Iga no Kami line continued through multiple generations down to the end of the Tokugawa period, while the Tanba no Kami line split into Kyo-Tanba (Kyoto) and Osaka-Tanba branches -- a division famously marked by differing renderings of the character mori in the signature. As the head of the lineage, Kinmichi possessed, generation after generation, the right to recommend to the Imperial Court regarding the granting of honorary titles to swordsmiths -- an institutional authority that reflected the school's preeminence within the capital's swordmaking establishment.
The technical foundation shared across the school is a forging of mixed with and , with a tendency toward standing grain -- a mannerism frequently identified as reflecting the school's origins. Thickly adhering with fine enter well, and the steel often shows a slightly blackish tone. The school's defining contribution to the canon is the ("bamboo-blind temper"), devised by Tanba no Kami Yoshimichi and developed across successive generations. In its original form, the begins with a long , above which the broadens into mixed with ; at the , vigorous and intermingle while persistent creates the distinctive striped appearance that gives the pattern its name. The Bengi remarks that in the first generation's work "within the patterned composition of the there resides the spirit of " -- a characterization that captures the essential quality of the 's approach, in which and break forth in semi-cursive (gyoso) disorder rather than the more technical and exaggerated rendering of later generations. The throughout the school typically rises with a tendency and vigorous -- the so-called " ," a -tendency turn with a pointed return that Masatoshi expressed "with particular clarity." Beyond the , the school's stylistic range was remarkably broad. Kinmichi worked across the -, Seki-, , and - with high command; Masatoshi, recognized as the most dexterous among the brothers, produced accomplished works in the manner of , Kaneshige, Kanemoto's , Yamato , and even ; and later generations absorbed the influence of Osaka fashion, producing flamboyant toran-style - alongside the inherited idiom.
The school's significance within the tradition rests on its dual achievement: the invention of the , one of the most immediately recognizable temper patterns in the Japanese sword canon, and the extraordinary technical versatility of its founding generation. The 's evaluative language for the school's finest works consistently returns to qualities of power, depth, and variety. Yoshimichi's is praised for "force and depth of taste" that distinguishes it from later generations' more formulaic output. Masatoshi's boldly varied patterns convey "a spirited and assertive character," while Kinmichi's large, turbulent in the -like manner overflows "with vigor and commanding spirit." The school's and strongly manifest the period character of the and early eras in their wide , thick , and greatly extended -- heroic forms that embody the martial confidence of their age. That the elder Kanemichi's inheritance was transformed within a single generation into the bold, -laden Kyoto manner speaks to the creative vitality of the founding brothers, while the school's longevity -- continuous production from the Eiroku era to the end of the Tokugawa period -- confirms the durability of the tradition they established.