Seijo-in, an adopted daughter of Ieyasu TOKUGAWA and the lawful wife of Kiyomasa KATO, was Katsunari's father Tadashige's daughter, that is, a younger sister of Katsunari.
加藤清正の正室、徳川家康養女清浄院は、実は勝成の父忠重の女、即ち勝成の妹である。