Takeda Yoshinobu served as a bushō during the Sengoku period.  He was the eldest son and designated heir of Takeda Harunobu (Shingen), the nineteenth head of the Kai-Takeda clan and sengoku daimyō of Kai Province.  Despite his position as the designated heir, Yoshinobu was removed from the line of succession owing to an event known as the Yoshinobu Incident.

Yoshinobu was born in 1538.  He was the grandson of Takeda Nobutora who unified Kai Province.  In 1536, Harunobu wed as his formal wife the daughter (Sanjō-fujin) of a noble named Sanjō Kinyori.  This was facilitated through Imagawa Yoshimoto, the sengoku daimyō of Suruga Province allied with the Takeda clan.  In 1550, at the age of thirteen, he attended his coming-of-age ceremony.  On 4/8, he received as his formal wife Yoshimoto’s daughter named Reishōin.  His mentor was Obu Toramasa, a senior retainer of the Takeda.  In the eighth month of 1552, he attended a ceremony to dress in armor for the first time.

On 12/29 of Tenbun 22 (1553), for the first time in the history of the Takeda clan, Yoshinobu received the character “yoshi” from Ashikaga Yoshifuji (later known as Yoshiteru), the thirteenth shōgun of the Muromachi bakufu.  This character was used by members of the Ashikaga shōgun family and Seiwa-Genji.  A west quarter was added to the residence in Kōfu for Yoshinobu.

In 1554, Yoshinobu participated in his first battle, an attack against the Chiku clan in the Saku District of Shinano.  After subduing a rebellion by the Chiku, Yoshinobu forced the surrender of those at Komoro Castle and led forces from Uchiyama Castle to capture and kill 300 fallen bushō.

In 1558, following the appointment of Harunobu as the military governor of Shinano, Yoshinobu was conferred the title of vice third deputy shōgun.  In 1561, Yoshinobu fought valiantly in the Fourth Battle of Kawanakajima.  During this event in the ninth month, after learning that the main division of Uesugi Kenshin was resting after trouncing the Takeda army, Yoshinobu led 800 soldiers on a mission.  He laid down the war banner of the Takeda army and, with a short sword, secretly approached the Uesugi forces under cover of the reed, launching a surprise attack against the enemy position.  Caught off-guard, a majority of the Uesugi forces fled in defeat, while chief retainers including Shida Genshirō Yoshitoki and Ōkawa Suruga-no-kami Takashige were killed.  Even Kenshin was forced to defend himself with an antique spear.  The Uesugi were on the verge of defeat until the arrival of Irobe Shū-no-jō Nagazane with 500 men and Usami Sadamitsu with over 1,000 men imposing a pincer attack on Yoshinobu’s forces.  Together with those from the main division of the Uesugi, these forces finally drove away Yoshinobu and his men to the Hirose Crossing.

In the tenth month of 1565, owing to a plot to assassinate Shingen, Yoshinobu was incarcerated in the Tōkō Temple in Kōfu.  On 10/19 of Eiroku 10 (1567), he died at the Tōkō Temple at the age of thirty.  In the eleventh month, his formal wife, Reishōin, returned to the Imagawa family in Suruga Province.

Yoshinobu Incident

In the seventh month of 1564, Yoshinobu’s mentor, Obu Toramasa, and close associates including Nagasaka Gengorō and Sone Suō-no-kami held secret meetings to plot the assassination of Shingen.  The plan, however, was discovered in a secret letter from Obu Saburō Hyōe-no-jō (Yamagata Masakage), the younger brother of Toramasa.  In the first month of 1565, Toramasa and those under him were executed for being ringleaders and eighty members of his band of retainers were expelled.

In the tenth month, Yoshinobu was incarcerated at the Tōkō Temple in Kōfu.  In addition to being compelled to separate from Reishōin, he was removed from the line of succession.  On 11/13, Shingen fostered closer relations with the Oda by arranging for his fourth son, Suwa Katsuyori (Yoshinobu’s younger brother of a different mother) to wed the adopted daughter of Oda Nobunaga named Ryūshōin.  Other factors in the background of the plot included the course of events related to the Fourth Battle of Kawanakajima and Yoshinobu’s resentment arising from the appointment of Katsuyori as the lord of Takatō Castle.

The details of the Yoshinobu Incident are uncertain.  The deterioration in relations between the Takeda and Imagawa clans in the wake of the incident, however, was compounded by preceding events.  These included the killing of Imagawa Yoshimoto at the Battle of Okehazama in the fifth month of 1560, followed by changes to the external policies of the Takeda clan permitted by a period of stability in northern Shinano after the Fourth Battle of Kawanakajima in 1561.  In 1568, the Takeda commenced the Invasion of Suruga against the territory of the Imagawa.  It is surmised that, in the background of the incident, there was tension between the faction led by Yoshinobu favoring close relations with the Imagawa and the faction led by Shingen seeking to invade the Imagawa territory.  In addition, the alliance between Shingen and Oda Nobunaga arose out of the need to resolve recurring conflicts that occured between the clans.  These began in the Eiroku era (1558 to 1570) in eastern Shinano at the border of the respective territories of the clans.  The unwillingness of Yoshinobu and the Imagawa to accept these arrangements gave rise to serious divisions within the Takeda clan.

On 8/7 of Eiroku 10 (1567), written oaths of loyalty to Shingen from the band of retainers in the Takeda territory were offered at the Ikushima-Tarushima Shrine in the Chiisagata District.  Under one view, this was aimed at calming the turbulence among the band of retainers after the Yoshinobu Incident.

In the sixth month of 1565, Nagasaka Gengorō and Sone Suō-no-kami donated a long sword to the Miwa Shrine located in the Kōfu Basin.  A letter dated 10/23 of Eiroku 8 (1565) from Shingen to Gengorō of western Kōzuke notes that Shingen discovered the secret plot by Obu Toramasa and the others so he immediately punished them.  Based on this correspondence, Toramasa’s death was between the ninth and tenth months of 1565.  This is further substantiated by memorial records from the Seikei Temple on Mount Kōya indicated that Toramasa died on 10/15 of Eiroku 8 (1565).

In southern Kai, the territory of Kawachi was adjacent to Suruga.  The Anayama clan, who were members of the Takeda family, governed Kawachi.  In the era of Anayama Nobutomo and Anayama Nobutada (father and son), the Anayama were relatives of the Takeda, serving as intermediaries for the alliance between the Takeda and the Imagawa, including, in 1552, for the marriage between Yoshinobu and Reishōin.  While affiliated with the main branch of the Takeda, the Anayama also cultivated close relations with the Imagawa.  At the end of 1568, however, when the Takeda launched the Invasion of Suruga against the territory of the Imagawa, the Anayama led the military operations.

With respect to the Yoshinobu Incident, the role of the Anayama clan is uncertain.  On 12/5 of Eiroku 9 (1566), Anayama Hikohachirō (Nobuyoshi), the younger brother of Anayama Nobutada (the head of the clan), took his own life in a minor temple on the grounds of the Kuon Temple on Mount Minobu.  During the Yoshinobu Incident, Nobutada affiliated with the faction supporting Shingen, so there is a possibility that internal discord erupted if Hikohachirō joined the faction backing Yoshinobu.