Kiyomitsu is one of the most prolific names among the smiths of the late period, the group collectively referred to as . Reference works such as the Hayami Shokunin enumerate some ten swordsmiths who bore the name, distinguished by various common appellations (tsusho) including Gorozaemon no Jo, Magoemon no Jo, Yosazaemon no Jo, Hikobei, and Magobei. Among these, Gorozaemon no Jo Kiyomitsu and Magoemon no Jo Kiyomitsu are known as superior craftsmen and stand at the head of the group in terms of technical level. Signed works by Gorozaemon no Jo appear from the Tenbun era onward, while Magoemon no Jo is attested across the Eiroku and Genki eras, with evidence suggesting two generations bearing that title. A further smith titled Jiemon no Jo Kiyomitsu, not recorded in the standard signature references (), is also known from a dated Genki 3 (1572) blade, making such pieces precious as material that helps fill gaps in the documentary record. The earliest Kiyomitsu signatures encountered bear Joji-era dates, and the lineage extends through the Tensho era at the close of the period.
Like other smiths, the Kiyomitsu line worked over a broad range of styles; however, the most numerous and finest works are those that take wide as their principal theme. In this mode the is typically a mixed with , into which and enter conspicuously, tempered in well-developed with a bright and clear . Fine and frequently appear within the hardened edge. The forging characteristically shows mixed with , with the grain standing slightly () -- a tendency that distinguishes Kiyomitsu from contemporaries such as Tadamitsu and Sukesada, who also produced . In the best examples, the is formed without irregular clustering and the is notably refined, with adhering well and entering abundantly; a faint suggestion of sometimes appears. Beyond , Gorozaemon no Jo also produced works in large , varied with (opened-waist) character, and incorporating and vigorous -- demonstrating a versatility characteristic of the strongest makers. The typical blade form is the late- shape: with wide , thick , high , conspicuous , and an extended , presenting a robust and dignified overall form suited to the martial demands of the Sengoku era.
The Kiyomitsu smiths occupy a position of particular significance within the tradition. Their sustained activity across multiple generations and common names reflects the enormous demand for swords during the Warring States period, and surviving works document the movements of these craftsmen beyond -- as evidenced by a blade forged by Gorozaemon no Jo while staying in the castle town of Tatsuno in Harima Province. A commissioned blade by Magoemon no Jo bearing the name of Utagami Munekage, the deputy military governor () of , further attests to the patronage these smiths received from the warrior elite. While the has noted that Kiyomitsu's can be inferior when compared with that of leading contemporaries such as Sukesada and Katsumitsu, the finest examples display a mastery of that is unsurpassed among makers, with bright and clear and , ample , and a vigorous spirit that embodies the cutting-oriented strength for which the late school is celebrated.