Lifespan: Unknown to 8/2 of Eiroku 9 (1566)
Title: Governor of Bizen, Master of the Western Capital Office (honorary)
Father: Tominaga Masayasu
Wife: Daughter of Matsudaira Nagachika
Tominaga Tadayasu served as a bushō during the Sengoku period. He was a retainer of the Tōjō-Kira clan and lord of Muro Castle in the Shitara District of Mikawa.
The Tominaga clan were descendants of the Tomo clan and owners of the Tominaga manor in the Shitara District. The Tominaga served as hereditary retainers of the Tōjō-Kira clan and as the lord of Muro Castle for successive generations.
Tadayasu allied with Matsudaira Hirotada after Hirotada was ousted by Matsudaira Nobusada. On 9/10 of Tenbun 5 (1536), Tadayasu welcomed Hirotada to Muro Castle. However, after an attack by the forces of Nobusada, on 10/7, he set fire to the castle while Hirotada went to Imabashi.
According to one account, during the Eiroku era (1558 to 1570), Tadayasu lived in a residence in Noda in the Shitara District in the Tominaga territory, but, after the fall of the Kira clan, in the third month of 1564, he moved to Ugaike. He was reported to have died on 8/10 of Eiroku 9 (1566).
Based on another account, in 1539, Kira Mochihiro joined forces with the Oda clan and severed relations with Imagawa Yoshimoto. Meanwhile, his younger brother, Arakawa Yoshihiro, allied with Yoshimoto and allowed the Imagawa army into his base at Arakawa Castle. This led to frequent clashes on Mount Arakawa (Mount Yatsuomote) near the castle. In a battle on 8/2, Mochihiro and Tadayasu were both killed in action. The death register of the Tominaga clan at the Daitsū Temple in Nishio indicates that members of the Tominaga clan died in battle on Mount Arakawa on this date.