Yoshihime

Yoshihime (1548-1623) was born at Yamagata Castle as the daughter of Mogami Yoshimori, a sengoku daimyo of Dewa Province, and was two years younger than her brother Mogami Yoshiaki. In 1564 she married Date Terumune, lord of Yonezawa Castle, and in 1567 bore his heir Bontenmaru (later Date Masamune), followed the next year by a second son, Kojirō.

Whenever military tension flared between the Date and Mogami clans, Yoshihime is said to have personally traveled to the battlefield to mediate between the two sides. She is recorded as having intervened around the Battle of Hitotoribashi (1585) and other clashes between her natal and marital families, playing an important role as a political go-between despite her difficult position caught between the two houses.

Yoshihime is most widely known for the alleged attempt to poison Masamune in April of Tenshō 18 (1590). According to traditions such as the Teizankō Chikeroku, she plotted to install her second son Kojirō as head of the Date clan and poisoned Masamune's food; he survived with stomach pain and vomiting, then killed Kojirō with his own hand and banished Yoshihime to her family's Mogami domain.

Recent scholarship, however, has raised serious doubts about the historicity of this episode. Letters from the priest Kosai Sōotsu suggest that Yoshihime's actual flight to Yamagata occurred around Bunroku 3 (1594) — four years after the incident is said to have taken place — a timeline inconsistent with the traditional account. Moreover, affectionate correspondence between Masamune and Yoshihime continued in the years after the supposed incident, with mother and son exchanging poems and money, and Masamune repeatedly writing that he wished "to see my mother's face once more." Given these contradictions, recent researchers have suggested the poisoning story may have been staged to unify a divided Date retainer band, or fabricated as an excuse to explain Masamune's delayed arrival at the Siege of Odawara. The truth remains unresolved.

Yoshihime spent her final years in Sendai and died on July 16, 1623, at the age of 76. Her Buddhist name was Hōshun'in. As a woman of a sengoku daimyo house who quietly supported the consolidation of her son Masamune's power, her legacy — inseparable from the unresolved poisoning legend — continues to be debated today.