Lifespan: Unknown to 3/4 of Eiroku 7 (1564)
Clan: Honda (the family of Honda Hikohachirō)
Lord: Imagawa Yoshimoto → Matsudaira Motoyasu
Father: Honda Masatada
Children: Mitsutada, Mitsunori, Tadatsugu, daughter (second wife of Asahina Sasetsugu）
Honda Tadatoshi served as a bushō during the Sengoku period. He was the lord of Ina Castle in the Hoi District of Mikawa Province.
Tadatoshi was born as the son of Honda Masatada, a bushō in Mikawa. Honda Shigetsugu, known as Onisaguza, was from a branch of Tadatoshi’s family, and was the son of a cousin of Tadatoshi.
First, he followed the Imagawa clan of Suruga Province. In the eighth month of 1556, Tadatoshi participated in the Second Division in the Battle of Ameyama to subdue Okudaira Sadakatsu after he separated from the Imagawa clan. In the fifth month of 1560, when his lord, Imagawa Yoshimoto (a sengoku daimyō and the eleventh head of the Imagawa clan) invaded Owari Province, Tadatoshi dispatched his eldest son, Honda Mitsutada, on his behalf. After marching into Owari, the Imagawa army was attacked and Yoshimoto killed at the Battle of Okehazama. This created an opportunity for Matsudaira Motoyasu (later known as Tokugawa Ieyasu) to become independent of the Imagawa and consolidate control of Mikawa Province. With the Imagawa in decline, Tadatoshi abandoned them in favor of the Matsudaira clan.
The Mikawa Ikkō-ikki was an uprising the followers of the Ikkō sect in the western portions of Mikawa that lasted for approximately one-half year from 1563 to 1564. During this period, Tadatoshi built a fortress in Kozakai in the Hoi District to defend against allies of the Imagawa based at Yoshida Castle on the eastern shore of the Toyo River who were seeking an opportunity to restore the authority of the Imagawa in Mikawa. Meanwhile, he sent Mitsutada to support Ieyasu in Okazaki.
On 3/4 of Eiroku 7 (1564), he died in Ina Castle.