Taira no Tokiko (平 時子?, 1126–1185) was the wife of Taira no Kiyomori, mother of Taira no Tokuko, as well as grandmother of Emperor Antoku. Later she took the vows to become a nun, after which she was generally referred to by her Buddhist name as the "Nun of the Second Rank" (Nii no Ama 二位尼). According to the Tale of the Heike, Taira no Tokiko drowned herself during the Battle of Dan-no-ura together with the boy-Emperor Antoku. She also took with her into the sea the Sacred Sword, i.e., one of the Three Imperial Regalia of Japan.