Takagi Sadamune (高木貞宗) is said to have been a man of Takagi in Gōshū (Ōmi Province) and a disciple of Sadamune. The precise nature of their relationship has been debated since early times: one tradition held that Takagi Sadamune was the individual as Sadamune, while another proposed he was Sadamune's second generation. The prevailing modern view, based on comparative analysis of workmanship, regards them as separate individuals, with Takagi Sadamune most likely a pupil who trained under his master when Sadamune was invited by the Sasaki clan and resided in Ōmi. In terms of period, he is thought to have been active around the Enbun–Jōji eras of the period, roughly contemporaneous with Kyō , and together with he is recognized as having transmitted his master's style with fidelity. Only a very small number of signed works survive, chiefly in the form of small ; the great majority of blades attributed to him are pieces that have received attribution.
Takagi Sadamune's manner of workmanship closely resembles that of Sadamune, and the salient points of the tradition emerge strongly in both and . He particularly excelled at , a gentle undulating temper, and among his works there are examples in which is mixed in, sometimes incorporating and angular . The characteristically shows mixed with , often tending toward a somewhat standing grain; very fine adheres thickly, with entering abundantly, and in some pieces is observed. The displays deep with thickly adhering ; in places occurs, mixed with , while and run with great frequency through the tempered area. The typically shows with a turnback, and blades often bear skillfully executed including , , and . In construction, his tend toward a wide with an , presenting a powerful and magnificent form, while his shorter blades display the proportions and thin characteristic of the stylistic mode.
What distinguishes Takagi Sadamune's finest work is the brightness and clarity of both and — a luminous quality in which the steel is described as (clear) and the shines with brilliance. His blades are rich in internal such as and , and the manner in which thickly adhering occasionally breaks into imparts a distinctive sense of weight and depth. While his does not fully attain the supreme refinement of his master Hikoshirō Sadamune, it is consistently well-forged, and the best examples call to mind the work of Sadamune at a glance. Several of his works carry distinguished provenance, including pieces transmitted in the Hosokawa, Date, and Mōri families, with confirming attributions from the period onward. As an inheritor of the tradition working from Ōmi Province, Takagi Sadamune occupies a position of particular scholarly interest, representing the direct transmission of Sadamune's style into the provinces during the turbulent era.