Niwa clan
was the 6th Niwa "daimyō" of Nihonmatsu Domain, and 7th hereditary chieftain of the Niwa clan. His courtesy title was "Wakasa-no-kami", and his Court rank was Junior Fourth Rank, Lower Grade. He was the eldest son of Niwa Takahiro and was received in formal audience by Shōgun Tokugawa Yoshimune in 1741. He became "daimyō" in 1745 on the retirement of his father. In 1747, the domain was ordered by the shogunate to undertake flood control projects on the Kiso, Ibi and Nagara Rivers in Owari Province, work which was part of the 1754 Hōreki River incident. Takayasu was married to a daughter of Tokugawa Munenao of Kishū Domain. He predeceased his father in 1766. His grave is at the temple of Dairin-ji in Nihonmatsu.