Lifespan: Unknown to 12/21 of Eishō era (1504 to 1521)
Other Names: Shōtarō (childhood)
Title: Junior Fifth Rank (Lower), Governor of Sado
Father: Matsudaira Nobumitsu
Mother: Daughter of Makihara Matabei
Siblings: Moriie, 昌龍, Chikatada, Tomosuke, Mitsushige, Mitsuhide, Tadakage, Mitsuchika, Iekatsu, Chikamasa, Chikanori, sister (wife of Toda Munemitsu)
Matsudaira Tomosuke served as a bushi from the mid-Muromachi to Sengoku periods. Tomosuke was the founder of the Katanohara-Matsudaira family, an illegitimate branch of the Matsudaira clan of Mikawa Province.
Tomosuke was born as the fifth son of Matsudaira Nobumitsu, the third head of the main branch of the Matsudaira clan. Initially, he held land with a value of 700,000 mon in Nakayama in the Nukata District of Mikawa and, in 1480, received an increase worth 50,000 mon and moved to the Katanohara township in the Hoi District.
On 12/21 of one of the years during the Eishō era (1504 to 1521), he died in Katanohara. His age at the time of his demise is unknown.
To pray for the spirit of his father, Tomosuke’s son, Matsudaira Sadasuke, built the Kōchū Temple to the southwest of Katanohara Castle. The name of the temple has its origins in the posthumous Buddhist name of Tomosuke. According to one theory, his younger brother, Matsudaira Mitsushige, had strong ties to the Katanohara-Matsudaira family and, after the death of Tomosuke, built the Kōchū Temple to serve as a family temple for members of the Katanohara-Matsudaira.