Lifespan: 14xx to 2/9 of Eishō 5 (1508)
Title: Governor of Kii
Father: Matsudaira Nobumitsu
Mother: Daughter of Makihara Matabei
Siblings: Moriie, Masatatsu, Chikatada, Tomosuke, Mitsushige, Mitsuhide, Tadakage, Mitsuchika, Iekatsu, Chikamasa, Chikanori, sister (wife of Toda Munemitsu)
Wife: Daughter of Saigō Yoritsugu
Children: Chikasada, Masayasu, Sadamitsu
Matsudaira Mitsushige served as a bushō from the mid-Muromachi to Sengoku periods. Mitsushige served as the first head of the Ōkusa-Matsudaira family based in the Ōkusa township in the Nukata District of Mikawa Province.
Mitsushige was born as the fifth son of Matsudaira Nobumitsu, the third head of the Matsudaira clan of Mikawa.
During the Bunmei era (1469 to 1487), Saigō Yoritsugu (Danjōzaemon; the lord of Okazaki Castle) fought against Nobumitsu, and finally lost, whereupon Yoritsugu transferred the castle to Nobumitsu and retired to Ōkusa. As part of the settlement, Nobumitsu arranged for Mitsushige to wed Yoritsugu’s daughter and appointed him as the lord of Okazaki Castle and founder of the Ōkusa-Matsudaira family. This was called the Okazaki-Matsudaira family until 1524 when the castle was seized by Matsudaira Kiyoyasu of the Anjō-Matsudaira family.
Later, Mitsushige’s lineal heir, Matsudaira Chikasada (Sama-no-jō), died early without an heir so Nobusada, the natural son of Saigō Yoritsugu, was adopted to become the designated heir of Chikasada.
Mitsushige also built a fortress in the mountains to utilize as a refuge in times of danger. Based on a document issued by the Daiju Temple in 1494, while under the command of the lead family of the clan, he served in the capacity of a magistrate.
According to accounts written by Ōkubo Tadataka, a bushō who lived from the Sengoku to early Edo periods, in 1506, Imagawa Ujichika expelled the Shiba clan from Tōtōmi Province and then invaded Mikawa. To the east of the Yahagi River, in the central area of Okazaki, Matsudaira Nagachika of the Anjō-Matsudaira family clashed with Ujichika’s forces. The movements of the Okazaki-Matsudaira family at this time who held land across the river to the south are uncertain. Mitsushige died in 1508, but it is not known whether this occurred in the course of battle against the Imagawa army.
His sons included Matsudaira Chikasada (Sama-no-jō; the second head of the Ōkusa-Matsudaira), Matsudaira Masayasu (Danjōzaemon; the third head of the Ōkusa-Matsudaira), and Matsudaira Sadamitsu (Sakon-no-shōgen).
Mitsushige is regarded as the founder of the Kōchū Temple in Katanohara in the city of Gamagōri and is recorded to have died on 2/9 of Eishō 5 (1508).