Mari (真利) is a name recorded in sword signature compendia across several lineages — , Fukuoka , Katayama , and the school — and it is acknowledged by the that it is difficult to distinguish these homonymous smiths decisively by signature style alone. The Ko- Mari, whose activity is placed in the early period, is understood as one of the smiths of the Fukuoka group working before the school reached its greatest prosperity in the mid- era. A second-generation Mari is recorded as having worked at in Province during the Bun'ei era, traditionally described as a student of Norifusa who later moved to Katayama in Province.
The works attributed to Ko- Mari characteristically show mixed with , with a pronounced tendency toward ; fine adheres, appears, and stands out. The is built on mixed with and , with and entering well and adhering; and appear in places. The consistently observes that compared with , the is more prominent and shows "a slight air of technical sophistication," yet compared with the works of the mid- period, the hardened edge presents "a calmer and more archaic taste." The Mari, by contrast, is described as "a somewhat more restrained and gentle example," with mixed with and , accompanied by .
Mari's surviving works are prized for combining the classical restraint of the inheritance with the emerging decorative energy of the tradition. forms are described as "dignified and of high style," and both and are frequently noted as — sound and well-preserved. The signatures, cut with a characteristically thick chisel in bold two-character form, are themselves valued as documentary evidence. evaluations consistently emphasize that these blades are "notably well-made" and "rich in points of appreciation," reflecting both an abundance of and a variety of internal activities that produce what the examiners describe as a rich variety of expression.