Lifespan: 14xx to 5/30 of Meiō 5 (1496)
Title: Governor of Tanba
Lord: Saitō Myōchin → Saitō Myōjun → Toki Shigeyori
Father: Ishimaru Sanemitsu
Children: Toshimoto, Toshitaka, daughter (wife of Oda Hirosada)
Ishimaru Toshimitsu served as a bushō during the Sengoku period. He held the title of Governor of Tanba. His father was Ishimaru Sanemitsu, and children included Toshimoto, Toshitaka, and the wife of Oda Hirosada. Toshimitsu initially served under Saitō Myōchin of the Jizeiin family that held the real power in Mino. Toshimitsu was based in Funada Castle and referred to as the junior deputy military governor. Later, he was permitted to adopt the Saitō surname and became known as Saitō Toshimitsu.
The Ishimaru clan originated from Owari Province, and served as the kasai, or head of house affairs, for the Saitō clan. Toshimitsu served under Myōchin in the Ōnin-Bunmei War. On 10/29 of 1480, he joined an invasion of the Kuwana District of Ise Province, toppling Umedo Castle defended by the Eastern army. Following the death of his lord, Myōchin, on 2/21 of 1480, he then served Saitō Toshikuni (known as Myōjun), and expelled Saitō Toshifuji, the deputy military governor of Mino, to Ōmi in an event known as the Mino-Bunmei Conflict.
Support for Toki Motoyori
However, after Nishio Naonori (who also served as the head of house affairs) slandered Toshimitsu to Myōjun, Toshimitsu gradually became alienated from Myōjun and considered the option of supplanting the Saitō under whom he served. At that moment, he responded to a solicitation from Toki Shigeyori (the military governor of Mino who had differences with Myōjun) and Saitō Toshifuji (who had returned from Mino) to join forces and received permission from Toshifuji to adopt the name of Saitō Tanba-no-kami Toshimitsu serving as the junior deputy military governor.
In the twelfth month of 1494, Toshimitsu abandoned a plot to assassinate Myōjun after learning that Nishio Naonori had informed Myōjun. He then assembled forces at his base of Funada Castle in Mino and proceeded to attack Myōjun’s base at Kanō Castle. According to Shigeyori’s wishes, Toshimitsu temporarily settled with Myōjun on the basis that Nishio Nanori be expelled, but Shigeyori then further requested Toshimitsu to help him to remove his eldest son, Toki Masafusa, from the line of succession and appoint his fourth son, Toki Motoyori, to be the designated successor to the Toki clan. Meanwhile, Myōjun supported Masafusa as the successor, causing Toshimitsu to gradually come into conflict with Myōjun. These differences escalated into a succession struggle in the Toki clan.
Battle of Funada
In the sixth month of 1495, Toshimitsu backed Toki Motoyori in the Battle of Funada. Motoyori’s daughter was wed to Oda Tōsada, the head of the Yamato-no-kami branch of the Oda family and deputy military governors of Owari based in Kiyosu. Tōsada despised the Saitō so the Oda also got involved in the conflict.
On 6/19 of the same year, members of Toshimitsu’s family including Ishimaru Toshisada and Ishimaru Hidemichi defeated the Nishio clan who had been supporters of the Saitō. The Ishimaru then proceeded to surround Kanō Castle, but were subject to a counterattack and died in battle. In the seventh month, when Toshimitsu heard that Masafusa had attacked the Furuta clan who were his allies, he sent family members including Ishimaru Masanobu, as well as members of the Baba and Kunieda clans, but the defenders lost. Toshimitsu burned down and abandoned Funada Castle, and fled to the territory of the Rokkaku clan in southern Ōmi. In the ninth month of 1495, Shigeyori reluctantly transferred the role as head of the family and military governor to Masafusa.
Fall of Kidaiji Castle
To enable an attack against Oda Tōsada (who was allied with Motoyori), Toshimitsu’s son, Ishimaru Toshitaka, eyed an opening when the Oda were encamped in Owari. On 3/20 of 1496, with the rear guard supported by members of the Hosokawa, the Rokkaku, and the Kitabatake clans, Toshitaka assembled troops in southern Ōmi and, via the direction of Ise Province, invaded Mino. With Motoyori serving as commander-in-chief, and Bishadō (Toshifuji’s youngest son) as the vice-commander, the army split into two divisions for the advance. Owing to a change in the battle situation, Toshimitsu attempted to stop the advance by Toshitaka’s division, but Toshitaka refused. From Tsushima in Owari, the army marched through Takegahana and defeated the Saitō army in a clash at Sunomata. The forces then proceeded toward Shigeyori’s retirement base at Kidaiji Castle.
First, Shigeyori refused to allow Toshimitsu and his forces into the castle grounds, but after learning that Motoyori was with them, invited them inside and holed up in the castle. However, the castle was surrounded by forces led by Saitō Myōjun, including Oda Tōhiro (the head of the Ise-no-kami branch of the Oda and deputy military governor of the four upper districts of Owari) and Asakura Sadakage (Myōjun’s son-in-law). Members of the Rokkaku clan came as reinforcements for the defenders but were beaten by the Kyōgoku clan who were aligned with the Saitō. On 5/30, just before the castle fell, Toshimitsu overcame the insistence of his son, Toshimoto, to continue to hold out, and committed seppuku along with Toshimoto in exchange for Myōjun sparing the lives of Shigeyori and Bishadō (Saitō Toshifuji’s youngest son). Meanwhile, although Shigeyori was able to depart from Kidaiji Castle, Motoyori was not allowed to do so, and, having no other options, killed himself on 6/20 of 1496.