Takeda Toyonobu served as a bushō during the Sengoku period.
Toyonobu was the head of the Kazusa-Takeda clan founded by Takeda Nobunaga in the mid-Muromachi period. The clan was also known as the Chōnan-Takeda owing to their base at Chōnan Castle in Kazusa Province.
Toyonobu is deemed to have been adopted by Takeda Kiyonobu. There is a theory that he is the same individual as Takeda Nobuyuki (the third son of Takeda Shingen).
In 1560, Toyonobu donated a portrait of sixteen benevolent deities to the Kasamori Temple in Kazusa.
On 2/8 of Genki 3 (1572), a letter was sent from Takeda Shingen stating a desire for assistance to reconcile with the Satomi and Gohōjō clans.
In 1576, Toyonobu left the Satomi clan and came under the command of Ashikaga Yoshiuji, the Koga kubō.
In the third month of 1582, the Conquest of the Kōshū by the Oda decimated the Kai-Takeda clan. Thereafter, Kanai Hidekage (Kuragano Hidekage) served as a deputy to Takigawa Kazumasu, a senior retainer of Oda Nobunaga, and urged Toyonobu to serve the Oda but Toyonobu declined to do so.
In 1590, during the Conquest of Odawara by Toyotomi Hideyoshi, Toyonobu was either neutral or allied with the Gohōjō clan. It is unclear, however, whether he holed-up in Odawara Castle. In the seventh month, he was attacked by Hideyoshi’s army and was defeated in battle against Honda Tadakatsu, a hatamoto under Tokugawa Ieyasu. He is regarded to have committed seppuku, but under another theory, fled and lived in confinement.
There is a grave for Toyonobu at the Dairin Temple in the town of Chōnan. He is said to have been buried after being killed in battle in 1590. After the fall of Chōnan Castle, his lineal heir, Takeda Ujinobu, settled in Nishimura.
Based on genealogical records, Toyonobu died on 7/7 of Tenshō 18 (1590).
According to accounts of the Kazusa-Takeda clan, Takeda Nobuyuki, the third son of Takeda Shingen and his formal wife, Sanjō-no-kata, was adopted by the Kazusa-Takeda clan and was the same individual as Toyonobu.
Based on other theories, he originated from an illegitimate branch of the Kazusa-Takeda or from the Kazusa-Taga clan but owing to a lack of authenticated records of the Kazusa-Takeda, these cannot be confirmed.
After the Conquest of Odawara, his position vis-à-vis the Gohōjō and Toyotomi Hideyoshi was unclear so the Chōnan-Takeda clan, along with the Mariyatsu-Takeda clan, fell into ruin. His son, Ujinobu, with the support of Umezawa Zusho, among others, fled to the village of Yamauchi in the Kamihabu District of Kazusa and settled there.