Isshiki Yoshisada (一色義定)
Yoshisada ISSHIKI (year of birth unknown - September 24, 1582?) was the family head of the Isshiki clan. A son of Yoshimichi ISSHIKI, and his other names were Yoshiari, Yoshitoshi and Mitsunobu. His commonly used name was Goro. His wife was Iya, a daughter of Yusai HOSOKAWA (in "Isshiki Gunki" [the war chronicle of the Isshiki clan], she is referred to as "Kiku no kata").
Yoshisada was a strong general who had valiance, and along with his father Yoshimichi, defended against the invasion by the Hosokawa's army which was under the control of Nobunaga ODA. In 1579 when his father was killed by betrayal of a partisan, Yoshisada took over as the head of the family. He led the remnants of the Isshiki clan for a do-or-die resistance at Yuminoki-jo Castle.
Thus, Mitsuhide AKECHI compromised with him by having Yoshisada marry the daughter of Yusai HOSOKAWA. He served Nobunaga since then. He attended the great military parade in Kyoto in 1581, and along with the Hosokawa clan, joined the suppression of the Takeda clan along with the Hosokawa clan.
At the Battle of Yamasaki in 1582, however, Yoshisada sided with Mitsuhide AKECHI. Since Yoshisada was married to the daughter of Fujitaka, at first Hideyoshi TOYOTOMI gave silent approval to him. However, when Hideyoshi reported to Tadaoki HOSOKAWA that Yoshisada was planning a rebellion, Fujitaka and Tadaoki, who were suspicious about Yoshitada, invited him to Miyazu-jo Castle and killed him by a deceptive attack.
When Yoshisada was killed, all the vassals who went into the castle were also killed. A hundred zohyo who were waiting at the castle town were also defeated by an army led by Yasuyuki MATSUI and Motomasa YONEDA, which resulted in the fall of Yuminoki-jo Castle. Yoshisada's wife Iyo went back to the Hosokawa clan when the castle was surrendered.
According to "Isshiki Gunki," Yoshitoshi (Yoshisada) was killed in February, which was before the Honnoji Incident. However, according to "Tanshu sanke monogatari" (the tale of the three families in Tanshu), Yoshisada is said to have been killed in September; and the Buddhist mortuary tablet of 'Mitsunobu ISSHIKI' which exists at the Seirin-ji Temple in Kami-Miyazu also says the date of Yoshisada's death was September 8.
Some people say that Shigeyuki ISSHIKI, who was a guest freeloader of Michikiyo ISHIKAWA in Niihama City, Iyo Province, was the third son of Yoshisada who survived the attack by the Hosokawa clan. Shigeyuki's descendants became shoya (village headman) by the end of the Edo period.