Lifespan: 15xx to 3/11 of Tenshō 10 (1582)
Title: Assistant Director of the Bureau of Palace Kitchens, Governor of Owari
Lord: Takeda Harunobu → Takeda Katsuyori
Father: Atobe Nobuaki
Siblings: Katsusuke, Yoshiyasu, two sisters
Children: Wada Nobunari, Masakatsu, daughter (wife of Asahina Nobuyoshi), daughter (wife of Yoda Nobushige)
Atobe Katsusuke served as a retainer for the Kai-Takeda clan of Kai Province. He was the son of Atobe Nobuaki.
The Atobe were a branch of the Ogasawara clan, shugo of Shinano Province, originating from the village of Atobe in Shinano. In 1416, Takeda Nobumitsu, the shugo of Kai Province, was decimated in a conflict known as the Uesugi-zenshū no ran. The Muromachi bakufu assigned Takeda Nobumoto and, thereafter, Takeda Nobushige who had entered the priesthood on Mount Kōya, to become the next shugo of Kai. The bakufu further ordered Ogasawara Masayasu, the shugo of Shinano, to support the return of the Takeda to Kai. Masayasu then dispatched the Atobe to serve as shugodai, or deputy shugo, to the Takeda, causing the Atobe to settle in Kai. In 1465, Takeda Nobumasa eliminated Atobe Kageie, and expelled the Atobe from Kai.
During the era of Takeda Harunobu (Shingen) and his son, Takeda Katsuyori, Atobe Katsutada and Atobe Masatada served as multi-generational elder retainers of the Takeda clan. Katsusuke and his father, Nobuaki, may have their origins in the Atobe who earlier served as shugodai of Kai. The expansion of territory controlled by the Takeda under Harunobu and Katsuyori resulted in a shortage of retainers stationed near the home base, so the sons and younger brothers of elder retainers served as attendants to their lord. Katsusuke, along with Yamagata Masakage, Tsuchiya Masatsugu, and Hara Masatane served as close associates of Harunobu and appear as signatories on official tax exemptions. Katsusuke commanded a contingent of three hundred mounted soldiers, one of the most powerful forces in the clan on a par with Yamagata Masakage and Kasuga Toratsuna.
In 1549, the Takeda subjugated kokujin families in the Saku District of Shinano, including the Mochizuki, the Ōi, and the Tomono. Katsusuke and Komai Kōhakusai were sent as messengers to serve as representatives of the Ōi clan on behalf of Ōi Nobutsune. From 1566, Katsusuke served as intermediary with kunishū in other territories. He acted as the magistrate for written vows that Harunobu had his retainers submit in the aftermath of the Yoshinobu jiken in the Takeda family.
While serving under Takeda Katsuyori, Katsusuke negotiated alliances with the Uesugi clan of Echigo Province and the Satake clan of Hitachi Province, often collaborating with Takeda Nobutoyo. In 1582, Katsusuke and Katsuyori perished in battle against the allied forces of the Oda and Tokugawa.
According to certain accounts, Katsusuke, together with another senior retainer of Katsuyori named Nagasaka Mitsukata, contributed to the fall of the Takeda clan. This owes to the confrontation between Katsusuke, as chief diplomat, and the elders, who comprised the military faction. In 1575, at the Battle of Nagashino, Katsusuke and Mitsukata advocated for battle, inviting the loss. In 1578, at a conflict known as the Otate no ran, Katsusuke and Mitsukata accepted a bribe of gold from Kagekatsu. In 1582, he abandoned Katsuyori and fled at the time that the clan faced its demise.
During the early years of Harunobu’s role as head of the clan, the seals of Katsusuke, together with Komai Kōhakusai, appear on many documents concerning diplomatic as well as provincial affairs, evidencing their roles as senior retainers in the clan.
Under Harunobu and Katsuyori, the domain governed by the Takeda extended into surrounding provinces. Intermediaries such as Katsusuke performed a vital role in the midst of a fluid environment, representing the interests of the clan in diplomacy with kunishū from other provinces in their domain.
Meanwhile, capable retainers were assigned as chamberlains to protect castles throughout the expanding territory of the Takeda. Katsusuke served as a shuttōnin, or a chief diplomat for the clan based in Kōfu. Others serving in this capacity and whose seals appear on official documents included Tsuchiya Masatsugu and Hara Masatane. To an extent, these retainers formed an oligopoly in the arena of diplomatic affairs.