Lifespan: Ōei 11 (1404) (?) to 7/22 of Chōkyō 2 (1488) (?)
Other Names: Sakyō-no-suke
Title: Junior Fifth Rank (Lower), Governor of Izumi
Lord: Ise Sadachika
Father: Matsudaira Chikauji or Matsudaira Yasuchika
Mother: Daughter of Matsudaira Nobushige
Siblings: Nobuhiro, Nobumitsu, Masuchika, Hisachika, Morihisa, Iehiro
Wife: [Formal] Shinjōin (daughter of the Isshiki clan); daughter of Makihara Matabei
Children: Moriie, Masatatsu, Chikatada, Tomosuke, Mitsushige, Mitsuhide, Tadakage, Mitsuchika, Iekatsu, Chikamasa, Chikanori, sister (wife of Toda Munemitsu)
Matsudaira Nobumitsu served as a bushō from the mid-Muromachi period to the Sengoku period. Nobumitsu served as the third head of the Matsudaira clan of Mikawa Province. He was the founder of the Iwatsu-Matsudaira family and the seven-generation-prior grandfather of Tokugawa Ieyasu.
According to certain sources, Nobumitsu was the son of Matsudaira Yasuchika (the second head of the Matsudaira clan) and, based on other sources, he was the son of Matsudaira Chikauji (the first head of the Matsudaira clan). His mother was the daughter of Matsudaira Nobushige, a landowner in the Matsudaira township of Mikawa originating from the Kamō clan, while his wife was a daughter of the Isshiki clan (either Isshiki Mitsunori or Isshiki Muneyoshi).
Based on genealogical records of the clan, the heads of the Matsudaira clan can be confirmed from the era of Nobumitsu. The genealogy prior to Nobumitsu is not well-documented so circumstances leading to the rise of the Matsudaira clan are not verified.
Nobumitsu was a dogō, or small-scale landowner, in Mikawa. He founded the Iwatsu-Matsudaira family based at Iwatsu Castle. Around the time of the Ōnin-Bunmei War, Nobumitsu served Ise Sadachika, the director of the mandokoro, or government office managing claims with respect to finances and landholdings for the Muromachi bakufu.
In 1458, Nobumitsu attacked Sekiguchi Mitsuoki at Ganryakuji Castle. Mitsuoki was the head of the Imagawa-Sekiguchi family, a cadet family of the Imagawa clan who served as the military governors of Suruga Province. After toppling the castle, he assigned his eleventh son, Matsudaira Chikanori, to serve as its lord. Thereafter, he designated Nagasawa Castle as his residence. This castle was located nearby to the north of Ganryakuji Castle and formerly occupied by Mitsuokis’ younger brother, Nagasawa Naoyuki. As a result, the family was known as the Nagasawa-Matsudaira clan while Iwatsu Castle was also called Nagasawayama Castle. In 1461, he eliminated Yamashita Shōzaemon of Hokkyū Castle.
In the fifth month of 1465, upon the demand of Hosokawa Shigeyuki, the military governor of Mikawa, and, as a servant of Sadachika, upon orders of Ashikaga Yoshimasa (the eighth shōgun of the Muromachi bakufu), Nobumitsu suppressed an event known as the Nukata District Uprising. As recognition for his contributions, he received from the bakufu landholdings in Fukōzu and elsewhere that were previously owned by the ikki forces.
Nobumitsu wed his daughter to Toda Munemitsu, a capable bushō from eastern Mikawa who also served the Ise clan. During the Ōnin-Bunmei War, Nobumitsu associated with the Eastern Army and, together with Hosokawa Shigeyuki, the military governor of Mikawa, he defeated the Isshiki clan who were aiming to restore their power in Mikawa. He joined a lightening assault against Hatakeyama Kaga-no-kami, a member of the Hatakeyama clan associated with the Western Army based in Anjō Castle. He captured the castle and had his fifth son, Matsudaira Mitsushige, become the son-in-law of Saigō Yoritsugu, the lord of Okazaki Castle, placing Okazaki Castle under his control.
In the Sengoku period, Nobumitsu entered Anjō Castle and expanded his base of power in western Mikawa, building the foundation of the Matsudaira clan as a sengoku daimyō. Over the course of a long life, he had many children. According to one source, he had forty-eight. He dispersed his children, having them establish the Takenoya-Matsudaira, the Anjō-Matsudaira (which later became the main branch of the Matsudaira clan), the Katanohara-Matsudaira, the Okazaki-Matsudaira (Ōkusa-Matsudaira), the Goi-Matsudaira (Fukōzu-Matsudaira family), the Nomi-Matsudaira, the Marune-Matsudaira, the Makiuchi-Matsudaira, and the Nagasawa-Matsudaira.
Nobumitsu built the Banshō Temple in the village of Taki, the Shinkōmyō and Myōshin temples in Iwatsu. He died in Iwatsu Castle and was succeeded by his third son, Matsudaira Chikatada.
There are several theories regarding the lifespan of Nobumitsu which cannot be authenticated. These include: (a) Ōei 20 (1413) to 7/22 of Chōkyō 2 (1488): seventy-six years old; (b) Ōei 11 (1404) to 7/22 of Chōkyō 2 (1488): eighty-five years old; and (c) Ōei 8 (1401) to 7/23 of Chōkyō 3 (1489): eighty-nine years old.
A record of religious ceremonies at the Daiju Temple on 12/26 of Bunki 1 (1501) states that the death anniversary of Nobumitsu was on 7/22 so this is authenticated.