The historical model for Kiri-no-kata is Acha-no-Tsubone (real name: Iida Suwa). The daughter of a vassal of the powerful Takeda clan, Acha married a samurai allied with both the Takeda and Imagawa clans. She bore him two sons, but her husband died soon after. Tokugawa Ieyasu (Toranaga in Shōgun) probably knew her because he had been held hostage by the Imagawa family for a long time. Two years after she was widowed, Ieyasu invited her to become one of his concubines.
Ieyasu had several concubines, but in Acha he found the ideal partner. She was always at his side, even on the battlefields. During the Battle of Komaki-Nagakute, where the armies of Ieyasu and Hideyoshi were pitted against each other, she joined Ieyasu although she was pregnant. Due to the stress of the war, she miscarried and was unable to bear more children. As Ieyasu's First Lady, she took care of all the internal affairs of the clan and raised Ieyasu's children by other concubines. She also served as an intermediary in peace negotiations.