Also known as: Ohigashi-no-Kata (お東の方), nickname—Demon Princess of the Ouu (奥羽の鬼姫), Hoshunin (保春院).
Mother of Date Masamune, daughter of Mogami Yoshimori and younger sister of Mogami Yoshiaki, Yoshihime was born in Yamagata Castle in Dewa. She was given in marriage at the age of 19 to Date Terumune and bore him two sons, Date Masamune and Date Kojirou. She hated her first-born, Masamune, due to his one-eyed state, and favored his younger brother Kojirou. There was additional tension between them due to Yoshihime leaking information to her relatives in the Mogami Clan even while they were fighting with the Date Clan. In 1585, upon Terumune's death, she decided to have Masamune killed to allow Kojirou to become head of the Date clan.
In 1590, when Masamune was participating in Toyotomi Hideyoshi's campaign against Odawara Castle, Yoshihime personally brought Masamune a meal laced with poison. Though Masamune consumed the poison, he was able to counteract it with the antidote. He then had Kojirou commit seppuku. Afterwards, Yoshihime returned to the Mogami Clan.
In 1614, upon Mogami Yoshiaki's death, internal strife split the Mogami Clan. In 1622, Yoshihime could no longer sustain her status in the Mogami Clan, and asked Masamune to return, which he allowed. She went to live in Sendai Castle and died there a year later at the age of 76.
It was thought from the contents of the letters and poems mother and son exchanged that Yoshihime was reconciliated with Masamune in her latter years.