Tadakuni is the first-generation Hizen smith who signed Harima Daijō, and later Harima no Kami, Fujiwara Tadakuni. His earliest name was Hironori; in Kan'ei 11 (1634), at the age of thirty-seven, he received the title Harima Daijō and changed his name to Tadakuni, the earliest title-bearing work on record being dated Kan'ei 13. He was a pupil of the first-generation Tadayoshi, the founder of the Hizen school, and the son of Sōemon Yoshiie of the Hashimoto family; since he shared the founder's Hashimoto surname, the published sources judge him likely of the same lineage, and note that he received his title considerably earlier than the second-generation Ōmi Daijō Tadahiro of the main house. He was retained by the Ogi domain, one of the three Nabeshima branch houses of Saga, and was active as an Ogi-domain smith. In old age he took the tonsure under the name Kyūtetsu, and his work extends into the Tenna era.

The published sources read his hand in two manners and call him highly skilled in both, but they place his true strength in the flamboyant midare. His is a gunome-chōji and chōji-midare, the temper often broad, the clove heads at times round, mixing in gunome, angular elements and yahazu-like forms with scattered tobiyaki. Long ashi enter frequently, with yō, the nioi deep and ko-nie well adhering. Above all it is the sunagashi that names him. The sources say of one blade that sunagashi runs vigorously through the ha, and that among his school he is the one in whom it is most conspicuous: 「刃中に砂流しがさかんにかかり」[[c:1]], 「一派の中でも最もそれが目立つ」[[c:2]]. With it run kinsuji, and the nioiguchi is bright and clear. The other recurring note of his clove work is the reach of its ashi: in midareba, the published record holds, his distinctive feature is a chōji with long ashi, 「足長丁子に特色がある」[[c:3]].

The jigane beneath both his manners is the tightly forged Hizen ko-itame with ji-nie, the steel the school is known for. On his finest pieces it becomes the dust-fine ji-nie laid thickly with chikei entering, the ji bright and clear, and several blades carry the slight nagare toward the edge that the sources note in his late suguha work. Over that jigane his second face is the calm one. He tempers a naka-suguha, at times a broad suguha, deep in nioi, ashi and yō entering well, with fine kinsuji and sunagashi and at the habuchi a nijūba-like effect. The published sources record him plainly as skilled in both registers, 「直刃, 乱刃ともに上手」[[c:4]], and on one late suguha katana they observe that, against his usual habit, here the sunagashi is not especially prominent, 「さまで砂流しが目立たず」[[c:5]], the whole finished in a quiet, restrained dekiguchi that shows this comparatively small body of straight-temper work. The bōshi in both manners runs straight to a ko-maru, frequently with hakikake.

His record divides less by period than by manner, though the dated pieces let the late years be read. The Harima Daijō signature carries the body of his work; the Harima no Kami signature, used after his promotion and running through the Kanbun, Enpō and into the Tenna years, marks the later blades. One Enpō 2 (1674) katana takes as its principal tone a varied large ō-notare-midare mixed with chōji-like elements and tobiyaki, deep in nie and nioi, which the sources call a manner brimming with vigorous spirit. On his most ambitious clove work the temper widens a further degree into an ō-chōji-midare with ara-nie and even slight muneyaki, so high-tempered, the published commentary remarks, as to be rare among his blades, and they ask whether the first-generation Tadakuni was here aiming at the old Ichimonji: 「古作の一文字あたりを狙ったものであろうか」[[c:6]]. The same record places the difficulty of his oeuvre squarely on the table. Because the second generation was likewise appointed Harima no Kami, the first and second are hard to tell apart, and the sources note a view that much now called second-generation work may in fact be the first's.

What sets Tadakuni apart within his own school is exactly what the judges name. His jigane and his bright nioiguchi are the shared Hizen inheritance, the komenuka-fine ko-itame and the clear temper that every Tadayoshi-line smith owes to the founder. His own signature is laid over that inheritance: the long-ashi chōji-midare and, within it, the sunagashi that runs more conspicuously in his ha than in any other hand of the school. On one katana the published sources read the workmanship as at first glance recalling Naoe Shizu, 「一見直江志津などの風を見せて上手である」[[c:7]], the Yamato-tinged streaming temper a measure of how far his midareba reaches from the calm Hizen suguha standard. He stands as the school's most accomplished maker of the flamboyant clove temper, the branch hand who carried the Hizen jigane into a brighter, more active hamon than the main line pursued.

For the collector he is a signed and well-documented Shintō name whose work survives entirely at the Jūyō level. Fujishiro grades him Jō saku. He has no National Treasures and no Important Cultural Properties; his record runs instead through the Jūyō Tōken ranks, where his katana appear across many sessions and the published sources repeatedly call them representative or typical examples by this smith, both ji and ha clear and bright. One they single out as 「傑出の一口であり, 典型作でもある」[[c:8]], an outstanding and typical piece of his midare work. Several carry Yamano Ka'emon cutting-test inscriptions in gold inlay, documents of the edge as well as the hand, and a number bear chrysanthemum and crab-peony crests on the tang. The thirty-some designated blades on record are held in private and long-kept collections, their owners largely unrecorded, so a signed Harima Daijō or Harima no Kami Tadakuni is not beyond reach in the way a National Treasure is; it comes to the serious collector from time to time, with patience, and a fully realized flamboyant chōji example, in which his sunagashi runs at its most vigorous, is a thing to be sought out when it appears.

Tadakuni is the first-generation Hizen smith who signed Harima Daijō, and later Harima no Kami, Fujiwara Tadakuni. His earliest name was Hironori; in Kan'ei 11 (1634), at the age of thirty-seven, he received the title Harima Daijō and changed his name to Tadakuni, the earliest title-bearing work on record being dated Kan'ei 13. He was a pupil of the first-generation Tadayoshi, the founder of the Hizen school, and the son of Sōemon Yoshiie of the Hashimoto family; since he shared the founder's Hashimoto surname, the published sources judge him likely of the same lineage, and note that he received his title considerably earlier than the second-generation Ōmi Daijō Tadahiro of the main house. He was retained by the Ogi domain, one of the three Nabeshima branch houses of Saga, and was active as an Ogi-domain smith. In old age he took the tonsure under the name Kyūtetsu, and his work extends into the Tenna era.

The published sources read his hand in two manners and call him highly skilled in both, but they place his true strength in the flamboyant midare. His is a gunome-chōji and chōji-midare, the temper often broad, the clove heads at times round, mixing in gunome, angular elements and yahazu-like forms with scattered tobiyaki. Long ashi enter frequently, with yō, the nioi deep and ko-nie well adhering. Above all it is the sunagashi that names him. The sources say of one blade that sunagashi runs vigorously through the ha, and that among his school he is the one in whom it is most conspicuous: 「刃中に砂流しがさかんにかかり」[[c:1]], 「一派の中でも最もそれが目立つ」[[c:2]]. With it run kinsuji, and the nioiguchi is bright and clear. The other recurring note of his clove work is the reach of its ashi: in midareba, the published record holds, his distinctive feature is a chōji with long ashi, 「足長丁子に特色がある」[[c:3]].

The jigane beneath both his manners is the tightly forged Hizen ko-itame with ji-nie, the steel the school is known for. On his finest pieces it becomes the dust-fine ji-nie laid thickly with chikei entering, the ji bright and clear, and several blades carry the slight nagare toward the edge that the sources note in his late suguha work. Over that jigane his second face is the calm one. He tempers a naka-suguha, at times a broad suguha, deep in nioi, ashi and yō entering well, with fine kinsuji and sunagashi and at the habuchi a nijūba-like effect. The published sources record him plainly as skilled in both registers, 「直刃, 乱刃ともに上手」[[c:4]], and on one late suguha katana they observe that, against his usual habit, here the sunagashi is not especially prominent, 「さまで砂流しが目立たず」[[c:5]], the whole finished in a quiet, restrained dekiguchi that shows this comparatively small body of straight-temper work. The bōshi in both manners runs straight to a ko-maru, frequently with hakikake.

His record divides less by period than by manner, though the dated pieces let the late years be read. The Harima Daijō signature carries the body of his work; the Harima no Kami signature, used after his promotion and running through the Kanbun, Enpō and into the Tenna years, marks the later blades. One Enpō 2 (1674) katana takes as its principal tone a varied large ō-notare-midare mixed with chōji-like elements and tobiyaki, deep in nie and nioi, which the sources call a manner brimming with vigorous spirit. On his most ambitious clove work the temper widens a further degree into an ō-chōji-midare with ara-nie and even slight muneyaki, so high-tempered, the published commentary remarks, as to be rare among his blades, and they ask whether the first-generation Tadakuni was here aiming at the old Ichimonji: 「古作の一文字あたりを狙ったものであろうか」[[c:6]]. The same record places the difficulty of his oeuvre squarely on the table. Because the second generation was likewise appointed Harima no Kami, the first and second are hard to tell apart, and the sources note a view that much now called second-generation work may in fact be the first's.

What sets Tadakuni apart within his own school is exactly what the judges name. His jigane and his bright nioiguchi are the shared Hizen inheritance, the komenuka-fine ko-itame and the clear temper that every Tadayoshi-line smith owes to the founder. His own signature is laid over that inheritance: the long-ashi chōji-midare and, within it, the sunagashi that runs more conspicuously in his ha than in any other hand of the school. On one katana the published sources read the workmanship as at first glance recalling Naoe Shizu, 「一見直江志津などの風を見せて上手である」[[c:7]], the Yamato-tinged streaming temper a measure of how far his midareba reaches from the calm Hizen suguha standard. He stands as the school's most accomplished maker of the flamboyant clove temper, the branch hand who carried the Hizen jigane into a brighter, more active hamon than the main line pursued.

For the collector he is a signed and well-documented Shintō name whose work survives entirely at the Jūyō level. Fujishiro grades him Jō saku. He has no National Treasures and no Important Cultural Properties; his record runs instead through the Jūyō Tōken ranks, where his katana appear across many sessions and the published sources repeatedly call them representative or typical examples by this smith, both ji and ha clear and bright. One they single out as 「傑出の一口であり, 典型作でもある」[[c:8]], an outstanding and typical piece of his midare work. Several carry Yamano Ka'emon cutting-test inscriptions in gold inlay, documents of the edge as well as the hand, and a number bear chrysanthemum and crab-peony crests on the tang. The thirty-some designated blades on record are held in private and long-kept collections, their owners largely unrecorded, so a signed Harima Daijō or Harima no Kami Tadakuni is not beyond reach in the way a National Treasure is; it comes to the serious collector from time to time, with patience, and a fully realized flamboyant chōji example, in which his sunagashi runs at its most vigorous, is a thing to be sought out when it appears.