Kageyasu of is known from six designated blades, five and one prewar , and from the old genealogies that place him among the smiths. The Kokon Meizukushi and the Tensho-bon Meizukushi list him beside Kagehide and Kagenori, as the son or pupil of Kagehide, the younger brother of Mitsutada. The published sources at once qualify that placement: "Kageyasu's work does not resemble Kagehide's", and some of it reads like .
The question of where he belongs runs through every paper. Same-name smiths are recorded in , , and Yoshii, and the published sources say the line and the dating both remain open to study. One paper explains that, because extant Kageyasu show a manner shared with , he is provisionally handled as . Others decide blade by blade: of one they write that angular elements mixed into the temper here and there mark it "as belonging to the Kagehide group", and of an that "it is not seen as ; it is proper to regard it as of the Kagehide school".
His character lies in the . Over an that stands a little, with and a rising , he tempers mixed with in a small whose elements turn angular. and enter, the is applied evenly, and and run through it. The published sources name the angular small -based as "the great feature" of his work, and of one blade they write that it is "a fine work with a clear, bright temper". The runs straight to a .
A second manner keeps closer to . The temper stays -based with small and small mixed in, small entering and well applied, over a flowing with . Of a in this manner the published sources write that it is "a piece that brings the manner to mind". The two manners are not dated against each other in the record.
His blades are slender with and fumbari and a small , most of them shortened by with the signature preserved at the tang tip. The signature is a two-character , and the published sources note that "a two-character cut with a rather thick chisel is usual". A single stands apart in form, its thin and its inward curve sharp, and they call it "a typical work of the smith in both and ". That paper also sets his period: "his time is thought to be no later than that of Nagamitsu".
For the collector, Kageyasu is a smith of the record rather than of the market. His six designated blades are five and and one formerly held by Hosokawa Moritatsu. A signed Kageyasu comes to light only rarely, and its interest lies as much in the open question of his school as in the angular small that identifies his hand.