The second-generation Harima no Kami Tadakuni of is known through three signed designated in 1964, 1992 and 1995. The published sources record that he was the son of the first-generation Tadakuni, used the common name Danzaemon, first signed Harukuni (治国), and took the name Tadakuni after his father retired. His dated works run from the eighth month of Enpo 5 (1677) to the second month of Jokyo 2 (1685), and his period of activity is placed in the Jokyo and Genroku eras; surviving works are described as rare. On most of his tangs he cut a chrysanthemum crest on the and a crab-and-peony crest on the , which the published sources take to indicate 「恐らく近衛家と深い関係があったものであろう」 (probably a close connection with the Konoe family). One of the three tangs also bears the inscription 「以南蛮鍛作」, made with imported nanban iron.
Like his father he worked in two manners, a -ba of mixed with and a straight , and the three designated blades show both. His is consistently a well-packed with very fine adhering thickly and fine . The of 1995 begins with a straight and rises into mixed with , -like elements and , with abundant and , deep , thick with some coarser particles, , and running throughout; the is bright. The published sources read the deep , thick and bright as evidence of his skill, and 「また刃中総体に砂流しのかかった態には、忠国一派の伝統的な特色が察知される」 (in the running throughout the , the traditional character of the Tadakuni line can be discerned). They add that the straight is often found among other smiths, and call the blade a full display of the second generation's ability.
The of 1964 has a shallow with and , deep and well-formed , and . Of it the published sources write that the technique 「ところがこの作刀に見る技術は、父に優るものがあり、この時代の肥前刀工中でも屈指の一人であることがわかる」 (surpasses his father in places, showing him to be one of the foremost smiths of his day), and that besides work he was skilled in as well.
The side is represented by the of 1992, a blade with a somewhat wide , at the base, thick and deep , tempered in a with a hint of small , adhering evenly, fine and , and a bright . The published sources describe it as a refined work and place it at the summit of his small output: 「作品の少ない同作の中でも白眉であり」 (among the few works of this smith it is the finest).