Due to her intelligence, Ieyasu entrusted her with management of the family's affairs, sending her to negotiate peace during the Siege of Osaka.

[2] In 1589, after the death of Lady Saigo, Acha become adopted mother of Tokugawa Hidetada and Matsudaira Tadayoshi.

Ieyasu had been chosen by Hideyoshi as member of the Council of Five Elders to act as regent for his son (Toyotomi Hideyori) with Yodo-dono (Oichi's daughter and Oda Nobunaga niece).

This marriage was only of a political nature to fortify the alliance between the two most powerful samurai clans at the time.

In 1613, she served as the Tokugawa representative to resolve escalating conflicts with the Toyotomi clan during the Great Bronze Bell Incident.

Hideyori's mother, Yodo-dono, who acted as the de facto leader of the Toyotomi clan, stirred up intrigues with the Tokugawa.

She refused several offers made by Ieyasu and expelled the pro-Tokugawa servants from Osaka Castle.

In 1614, once again Lady Acha accompanied Ieyasu and the entire Tokugawa army into battle with the Toyotomi.

Lady Acha was accompanied by Honda Masazumi to meet Kyōgoku Tadataka, son of Ohatsu, younger sister of Yodo-dono.

During the meeting, Lady Acha assured Ohatsu that Ieyasu had no ill will towards Hideyori and that he wished to forgive him, but Hidetada was stubborn about taking the castle.

Lady Acha went to the enemy headquarters and held again a peace conference with Ohatsu and Okurakyo no Tsubone, maid of Yodo-dono.