Sanetada (実忠) was a swordsmith of Province, working from the village of Furuya in the Nishu region during the Eiroku era (1558--1570). He belonged to a lineage of Nishu smiths who shared the character Sane (実) as a generational element: Sanemasa and Sanehisa preceded him around the Tenbun era, while Sanetada and Sanenaga were active by the Eiroku period. According to sources, Sanetada is said to have been the son of Sanemasa; various genealogical records also describe him as either the father or grandfather of Kunihiro, or alternatively as representing Kunihiro's earliest working name. The precise nature of the relationship remains a matter of scholarly discussion, though the proximity of their dated works and the close correspondence in their chiseled signature forms attest to a direct and intimate connection.
Sanetada's forging is characteristically with areas of mixed grain showing a tendency toward (standing grain), over which very fine adheres thickly and fine enter well. His typically consists of mixed with and , linked at intervals by an extremely shallow , with and entering and the tending toward a tight appearance with adhering well. Fine and appear, and are seen throughout. This pointed-element temper closely resembles what is traditionally termed Kunihiro's "Furuya forging" (), reinforcing the lineage connection between the two smiths. His characteristically runs -cho with a pointed tendency and long turnback.
Extant signed works by Sanetada are exceedingly few. All bear Eiroku-era dates, and surviving examples encompass , , and blades in both and construction. Rated Jo by Fujishiro, Sanetada occupies a position of considerable documentary significance: his dated inscriptions and distinctive manner of signature provide essential source material for understanding the transition from the Nishu Sane-generation smiths to the -generation that followed, culminating in the celebrated work of Kunihiro himself.