Motomitsu was a swordsmith of the school active during the period. He is traditionally transmitted as either the son of Kanemitsu or as one of his montei (disciples), and he held the title Saemon no Jo. His customary signature reads "Bishu Motomitsu," though some examples add his fuller style, " no -ju Saemon no Jo Motomitsu." Among extant dated works, inscriptions range from Koei through Eiwa, making the span of his activity clearly ascertainable. Together with Rinko (also called Rinmitsu), he stands as a representative smith of the Kanemitsu lineage, and within that lineage he is distinguished from Rinko, who is known for work in which a small- basis predominates, by a temperament in which is conspicuously featured.
In style Motomitsu follows the manner of Kanemitsu. His forging is typically mixed with , tending toward (standing grain), with fine densely applied, entering, and standing out — variously described as , , or a straight -like form near the edge. His most characteristically employs as the principal motif, intermixed with angular , , , and passages tending toward . Works are frequently encountered in which of varied forms are intermingled within an irregular temper, as well as examples where the run in an orderly, consecutive succession. The is typically tight, the temper -dominant with adhering, and activities such as , , and occasional enliven both and . The characteristically enters in , turning back with a somewhat pointed tendency and at times showing fine . Some works, particularly among the , display a quieter -based temper in , executed in a calm manner that gives the sense of approaching Kanemitsu. His blades frequently exhibit the grand, imposing of the mid- era — wide , little taper from base to tip, and extended or — vividly expressing the period character of the age.
In terms of overall rank of workmanship, Motomitsu is regarded as yielding slightly to Kanemitsu, yet his finest works give the impression of approaching his master's level. The variety of temper elements and the vigorous internal activity of and produce abundant changing effects that are rich in scenic interest. Signed are comparatively few, and those retaining tang inscriptions with era dates — such as Bunwa, Joji, , and Sadaji — constitute valuable material for research on this smith. One such was transmitted in the Great Tokugawa family. His works are consistently praised for (sound and well-preserved) condition in both and , and for a clarity of that the descriptions characterize as — bright and clear.