Lifespan: 15xx to 5/26 of Eiroku 12 (1569)
Title: Governor of Sanuki, Head of the Imperial Cavalry of the RIght Division
Clan: Yokodake (an illegitimate branch of the Shōni)
Lord: Shōni Sukemoto → Shōni Fuyuhisa
Father: Yokodake Sukesada
Siblings: Sukemasa, Chiba Tanekatsu
Wife: Daughter of Shōni Fuyuhisa
Yokodake Sukemasa served as a bushō during the Sengoku period. He was a retainer of the Shōni clan and served as the lord of Nishijima Castle in Hizen Province. He had the common name of Hikoshirō.
The Yokodake were an illegitimate branch of the Shōni clan serving as the district governors of the Mine District. The family was founded by Shōni Yorifusa, the son of Shōni Sadayori, who adopted the surname of Yokodake.
Sukemasa was born as the son of Yokodake Sukesada.
In 1506, he received one of the characters from the name of Shōni Sukemoto and adopted the name of Sukemasa. He assisted Sukemoto and became a deputy to him.
In 1530, at the Battle of Tadenawate, acting upon orders of Ōuchi Yoshitaka (the Governor-General of Kyūshū), a retainer named Sue Okifusa mobilized forces in northern Kyūshū to attack the Shōni clan who were at a disadvantage. Sukemasa’s father, Sukesada, switched his allegiance to the Ōuchi, but Sukemasa remained loyal to the Shōni throughout the battle. Thereafter, he served in a key role on behalf of Sukemoto’s eldest son, Shōni Fuyuhisa, marrying Fuyuhisa’s daughter.
Sukemasa died in 1569.
Yokodake Sukeyoshi was the son of Sukemasa. He was also called Magojirō and Hyōgo-no-kami. He died on 9/29 of Tenbun 22 (1553).
Yokodake Shizusada was Sukeyoshi’s son. He was also known as Iezane, Yajūrō, Nakatsukasa-Taifu, Yorisada, and Fumitsune. He served as a retainer of Ōtomo Yoshishige (Sōrin). The Shōni clan were eliminated in 1559 so, in a bid to revive the clan, he fought against Ryūzōji Takanobu. Shizusada resided in the stronghold of Nishijima Castle. From 1563 to 1575, with the support of the Ōtomo and Tsukushi clans, he thwarted multiple attacks by the Ryūzōji. In 1570, he served in the Ōtomo army at the Battle of Imayama.
Later, after surrendering to Takanobu, Shizusada served under Ryūzōji Masaie and received one of the characters from the name of Masaie, adopting the name of Iezane. Thereafter, Iezane, together with a fellow family member named Yoritsugu, served in the Ryūzōji army during invasions of western Hizen and Chikugo Province. In 1585, Iezane honored the last will of his grandfather, Sukemasa, and donated a stone pagoda to Tajima Province.
According to one account, Iezane and Yoritsugu of the Yokodake clan has landholdings of 600 chō (approximately 600 hectares).