Lifespan: Daiei 4 (1524) to Keichō 17 (1612)
Other Names: Tōzō (childhood), Sanjūrō, Kodayū
Lord: Matsudaira Hirotada → Tokugawa Ieyasu
Father: Yonekizu Katsunobu
Siblings: Tsuneharu, Masanobu
Children: Masakatsu, Haruchika
Yonekizu Tsuneharu served as a bushō from the Sengoku to early Edo periods. He was a retainer of the Matsudaira clan and is counted among the Sixteen Divine Generals of the Tokugawa.
In 1524, Yonekizu was born as the lineal heir of Yonekizu Katsunobu. He originated from Yonekizu in the Hekikai District of Mikawa Province.
The Yonekizu clan were hereditary retainers of the Matsudaira clan for a long time. Tsuneharu, together with his father, Katsunobu, served Matsudaira Hirotada and Matsudaira Motoyasu (later known as Tokugawa Ieyasu).
In 1549, under the Matsudaira clan who were subordinate to Imagawa Yoshimoto, he attacked the Anjō Castle (the base of Oda Nobuhide in Mikawa) capturing its lord, Oda Nobuhiro. In 1560, during the Battle of Okehazama, Tsuneharu, together with his younger brother (Yonekizu Masanobu) and son (Yonekizu Masakatsu) served in the vanguard of Mikawa forces, joining in attacks on Marune and Ōdaka castles. In 1563, upon the outbreak of the Mikawa Ikkō-ikki, he quickly rushed to Okazaki Castle and worked closely with Ieyasu to suppress the uprising the following year.
In the final account of his exploits, Tsuneharu and Watanabe Moritsuna wielded spears at the Battle of Mikawa-Akazaka in 1564. The only record thereafter is a reference to his death in 1612 at the age of eighty-nine.