Yukihide was born in Bunka 10 (1813) at Hoshimaru in Asakura, Kamiza District of Province, the heir of Matabei Morishige, and took the name Toyonaga Kyūbei, later the art-name Tōko. He set the character (左) at the head of his signature and styled himself a descendant of the line, in some inscriptions its thirty-ninth generation, a genealogical claim the published sources flatly reject: of one dated the commentary states that he "styled himself the thirty-ninth-generation grandson of , but this is not correct" (三十九代の孫と称しているが当らない). What is documented instead is a career of the bakumatsu. In the early Tenpō era he went up to and studied sword-forging under Shimizu Hisayoshi, a disciple of Hosokawa Masayoshi, winning a name for surpassing his teacher; in Kōka 3 (1846), at thirty-four, he went down to Tosa at the recommendation of the domain smith Sekita Shinpei Katsuhiro, and in Ansei 2 (1855) he became a retained smith of the Yamauchi house, working in both Tosa and the domain's residence at Sunamura in Fukagawa until his swordmaking ended in Meiji 3 (1870). The published sources count him "one of the noted masters of the " (新々刀工中の名工の一人である).
His recognized work is a broad made in conscious emulation of Inoue Shinkai, the manner the published sources call his true forte. He carries it on a grand body, wide in with little taper from base to tip, thick in and heavy in the hand, shallow in with a large or elongated point, the tang and cut with a long, boldly chiseled signature. Over a tightly forged the temper runs a wide bearing a shallow and vigorously mixed with , the exceptionally deep, the thick and well adhered, - frequent along the , entering, with and running through and the whole bright and clear. The runs straight to a with and a long, sometimes deep, turnback. The dated Kaei 2 (1849) shows the type at its height, its broad straight temper with intermingled the most deeply -laden of his hand.
The is the constant beneath both his manners. It is a closely packed , at times an flowing toward , with thick , frequent , and a steel the commentary repeatedly calls bright and clear, occasionally tightening to a near-plain . This is the -derived forging of his stated ideal rather than any reflection, and the published sources hold that whatever the temper his is well attached, his the deepest, and his and keenly clear. On one Kaei 6 (1853) the activity is described with his and both luminous; on another the is "the deepest, bright and clear."
Alongside the the published sources name a second manner, a at times led by and mixing in and large , more flamboyant than the straight temper. Over the build the edge enters long thick , the deep, the thick and at times coarse, with and , and the runs and points or turns back in with . The forging beneath it ranges from the tight to a well-ordered . Some of these the commentary reads as after models, with a emulation among them and others recalling Nanki Shigekuni; his earliest manner is recorded as a Hosokawa-school -, a with a tightened , before he turned, in his own words and the judges', to the tradition. He also signed in several hands, sometimes adding a , and on a few late blades the seven-character Toyonaga Tōko signature.
What sets Yukihide apart from the wider revival is the object of his emulation and the clarity he drew from it. Where many of his contemporaries rebuilt the flamboyant of the middle ages, his ideal, as the published sources put it, was "to take the tradition as his ideal" (相州伝を理想とし), realized above all in works "after the manner of Inoue Shinkai, in conscious admiration of him" (井上真改に私淑した). His bright deep- over a -laden is read as the Ōsaka Shinkai line carried into the bakumatsu, and the judges go further still: of one Kaei 6 the commentary declares outright that "the brilliance of his and is foremost among the " (地刃の冴えは新々刀中第一である). That clarity, more than any single shape of temper, is the mark of his hand.
For the collector Yukihide is a securely knowable name, signed and dated almost without exception. Fujishiro grades him Jō-jō , and his record runs through two works at the rank, two prewar Jūyō Bijutsuhin, and many at the rank, sixty-three in the and tiers together; he has no National Treasures or Important Cultural Properties. Because, as the commentary warns, forgeries in his name are extremely numerous, a securely dated signature is prized as a reference specimen, and the supplementary inscriptions some of his blades carry, recording the place of forging and even the mochitetsu iron used, are valued as documentary material in their own right. His blades pass through long-held collections anchored in their own provenance, among them the Yamauchi lords of Tosa, in whose villa at Godaizan he forged what one entry calls a once-in-a-lifetime work, alongside the Inada, Ogura, Ochi and Takagaki families of recorded whereabouts. Most are held rather than traded, but he is not beyond reach as the great names are: a signed, dated Yukihide of good workmanship comes to market from time to time, a sound and bright record of the last age of the Japanese sword.