The Meikan record Kageyasu (景安) under "Bizen, around Genryaku"[[c:1]], the era of 1184 to 1185, and the NBTHK counts him among the smiths of the Ko-Bizen stream at the opening of the Kamakura period. His record divides into two signature registers: a rare group cut with the small, long signature Bizen no kuni Kageyasu[[c:2]], and a comparatively numerous group signed with two large characters in a thick chisel. The Kokon Meizukushi (古今銘尽) makes him an Osafune smith and a son of Kagehide, but the published sources reject the claim on the work itself, finding that the jiba and the manner of the utsuri are in the Ko-Bizen mode, so that the Osafune theory does not hold. Whether he belongs to Ko-Bizen or to the earliest Ichimonji is left open; that he does not descend later than the early Kamakura period is held firm. One tradition makes him a pupil of Yoshinori (義憲の門).

His hallmark the NBTHK names outright. The yakiba mixes, somewhere within an overall suguha-toned line, angular ha of gunome character[[c:3]], and between widely spaced gunome and choji it shows tobiyaki and yubashiri[[c:4]], traits the published sources call clearly distinctive. The commentary on his kodachi presses the point, observing that in most of the surviving works angular elements invariably accompany the temper somewhere along the edge. Honma Junji adds that even in the flamboyant pieces "an angular hamon mixes in somewhere in almost every case"[[c:5]]. The squared edge is matched by an unusual weighting of the temper. Where the habit of the old Bizen masters is ko-midare, gunome leads in his work, and choji stands further forward in his yakiba than in the Ko-Bizen peers Tomonari, Masatsune and Kanehira, in whose recorded blades the squared gunome does not appear at all.

The tachi form is slender, the koshizori high with pronounced funbari, the blade gathered into a ko-kissaki; of one long-signed tachi the published sources write that the figure is "beautiful and unmistakably refined"[[c:6]]. The jigane is itame, mixed in places with mokume and flowing hada, with a slight tendency to stand. Ji-nie adheres well, chikei enter, and a midare-utsuri rises, with jifu mixing on some blades. The temper works in ko-nie, either a suguha-toned ko-midare or a choji-midare mixed with gunome. Ashi and yo enter well, kinsuji and sunagashi appear, and the nioiguchi runs deep on some blades while tightening in places on others. The boshi as a rule runs sugu to a small round turnback, and the published record notes the habit that even where the lower half runs to midare, "the boshi tends to settle large and straight"[[c:7]]. On one katana the utsuri emerges only partially in bo-utsuri fashion, and the commentary reads that technically unfinished rendering as an archaic charm, strengthening a date before the middle Kamakura period.

The two registers carry the scholarship. The long-signature group, few in number, is judged correctly Ko-Bizen, and in the comparison "the long signature shows the more archaic air, and the characters of the signature are somewhat more naive"[[c:8]]; whether the difference from the two-character group is one of production date or of different men is, the published sources say, a matter requiring further study. Within the two-character signature itself a bold thick-chisel hand and a finer chisel are distinguished, so several smiths of the name are considered to have existed, the workmanship supporting the view; later homonyms worked in the Fukuoka and Yoshioka Ichimonji, the Osafune and the Yoshii lines. One tachi preserving only the character Ichi on its shortened nakago carries a Hon'ami origami of 1688 appraising it to Kageyasu at thirteen gold pieces, and Honma observes that its angular ko-gunome carries even a sealed-bid appraisal straight to Kageyasu[[c:9]], taking the blade as evidence that the smith stands in the Ichimonji line.

That bridge position defines his school role. The choji standing forward in his small irregular temper is read as the manner the earliest Ichimonji inherit, the published sources writing of one Tokubetsu Juyo tachi that "it seems that this manner of workmanship was later carried forward into Ko-Ichimonji"[[c:10]]. For so early a smith the works survive in relative number, and the Juyo Bijutsuhin commentary rates the hand plainly: his works are "comparatively numerous, and skilled"[[c:11]]. The record holds one singular document of form as well. Extant kodachi begin with the Ko-Bizen smiths of the early Kamakura period, and the signed kodachi by Kageyasu, an ubu blade of 53.5 cm with koshizori and funbari, is likely the only one from his hand.

Twenty-seven designated works stand on record, and against the habit of so early an age the record is overwhelmingly signed, twenty-three signed blades against four unsigned. One blade holds Important Cultural Property rank, one is recorded in the Imperial collection, and eight are Juyo Bijutsuhin, certified across the 1930s and 1940s. The tier a private collector may realistically encounter is the six Tokubetsu Juyo and eleven Juyo, though blades of this age are held long, and a signed Ko-Bizen tachi reaching the open market is a rare event. Of recorded whereabouts, his blades rest at Kashima Jingu, the Tsuchiura City Museum, the Sano Art Museum and the Samurai Art Museum in Berlin. Eleven blades carry recorded provenance, and the roll is distinguished: the Kan'in-no-miya house, whose Prince Haruhito held the signed Tokubetsu Juyo tachi; the Date of Sendai, with whom a tanto remained from early times; a branch of the Yonezawa Uesugi, in whose line the kodachi descended; the Migita Mori; and the Yanagisawa, whose blade came as a grant from the shogunal house and carries an old origami of 1661.

The Meikan record Kageyasu (景安) under "Bizen, around Genryaku"[[c:1]], the era of 1184 to 1185, and the NBTHK counts him among the smiths of the Ko-Bizen stream at the opening of the Kamakura period. His record divides into two signature registers: a rare group cut with the small, long signature Bizen no kuni Kageyasu[[c:2]], and a comparatively numerous group signed with two large characters in a thick chisel. The Kokon Meizukushi (古今銘尽) makes him an Osafune smith and a son of Kagehide, but the published sources reject the claim on the work itself, finding that the jiba and the manner of the utsuri are in the Ko-Bizen mode, so that the Osafune theory does not hold. Whether he belongs to Ko-Bizen or to the earliest Ichimonji is left open; that he does not descend later than the early Kamakura period is held firm. One tradition makes him a pupil of Yoshinori (義憲の門).

His hallmark the NBTHK names outright. The yakiba mixes, somewhere within an overall suguha-toned line, angular ha of gunome character[[c:3]], and between widely spaced gunome and choji it shows tobiyaki and yubashiri[[c:4]], traits the published sources call clearly distinctive. The commentary on his kodachi presses the point, observing that in most of the surviving works angular elements invariably accompany the temper somewhere along the edge. Honma Junji adds that even in the flamboyant pieces "an angular hamon mixes in somewhere in almost every case"[[c:5]]. The squared edge is matched by an unusual weighting of the temper. Where the habit of the old Bizen masters is ko-midare, gunome leads in his work, and choji stands further forward in his yakiba than in the Ko-Bizen peers Tomonari, Masatsune and Kanehira, in whose recorded blades the squared gunome does not appear at all.

The tachi form is slender, the koshizori high with pronounced funbari, the blade gathered into a ko-kissaki; of one long-signed tachi the published sources write that the figure is "beautiful and unmistakably refined"[[c:6]]. The jigane is itame, mixed in places with mokume and flowing hada, with a slight tendency to stand. Ji-nie adheres well, chikei enter, and a midare-utsuri rises, with jifu mixing on some blades. The temper works in ko-nie, either a suguha-toned ko-midare or a choji-midare mixed with gunome. Ashi and yo enter well, kinsuji and sunagashi appear, and the nioiguchi runs deep on some blades while tightening in places on others. The boshi as a rule runs sugu to a small round turnback, and the published record notes the habit that even where the lower half runs to midare, "the boshi tends to settle large and straight"[[c:7]]. On one katana the utsuri emerges only partially in bo-utsuri fashion, and the commentary reads that technically unfinished rendering as an archaic charm, strengthening a date before the middle Kamakura period.

The two registers carry the scholarship. The long-signature group, few in number, is judged correctly Ko-Bizen, and in the comparison "the long signature shows the more archaic air, and the characters of the signature are somewhat more naive"[[c:8]]; whether the difference from the two-character group is one of production date or of different men is, the published sources say, a matter requiring further study. Within the two-character signature itself a bold thick-chisel hand and a finer chisel are distinguished, so several smiths of the name are considered to have existed, the workmanship supporting the view; later homonyms worked in the Fukuoka and Yoshioka Ichimonji, the Osafune and the Yoshii lines. One tachi preserving only the character Ichi on its shortened nakago carries a Hon'ami origami of 1688 appraising it to Kageyasu at thirteen gold pieces, and Honma observes that its angular ko-gunome carries even a sealed-bid appraisal straight to Kageyasu[[c:9]], taking the blade as evidence that the smith stands in the Ichimonji line.

That bridge position defines his school role. The choji standing forward in his small irregular temper is read as the manner the earliest Ichimonji inherit, the published sources writing of one Tokubetsu Juyo tachi that "it seems that this manner of workmanship was later carried forward into Ko-Ichimonji"[[c:10]]. For so early a smith the works survive in relative number, and the Juyo Bijutsuhin commentary rates the hand plainly: his works are "comparatively numerous, and skilled"[[c:11]]. The record holds one singular document of form as well. Extant kodachi begin with the Ko-Bizen smiths of the early Kamakura period, and the signed kodachi by Kageyasu, an ubu blade of 53.5 cm with koshizori and funbari, is likely the only one from his hand.

Twenty-seven designated works stand on record, and against the habit of so early an age the record is overwhelmingly signed, twenty-three signed blades against four unsigned. One blade holds Important Cultural Property rank, one is recorded in the Imperial collection, and eight are Juyo Bijutsuhin, certified across the 1930s and 1940s. The tier a private collector may realistically encounter is the six Tokubetsu Juyo and eleven Juyo, though blades of this age are held long, and a signed Ko-Bizen tachi reaching the open market is a rare event. Of recorded whereabouts, his blades rest at Kashima Jingu, the Tsuchiura City Museum, the Sano Art Museum and the Samurai Art Museum in Berlin. Eleven blades carry recorded provenance, and the roll is distinguished: the Kan'in-no-miya house, whose Prince Haruhito held the signed Tokubetsu Juyo tachi; the Date of Sendai, with whom a tanto remained from early times; a branch of the Yonezawa Uesugi, in whose line the kodachi descended; the Migita Mori; and the Yanagisawa, whose blade came as a grant from the shogunal house and carries an old origami of 1661.