According to an article on March 24th of the second year of the Genryaku era (May 2, 1185) in the 'Azuma Kagami' (a Japanese medieval history book), "Taira no Tokiko (her Buddhist name was 'Nii no Ama'), who held the sacred sword (Amakumo no Tsurugi), and Azechi, a lady-in-waiting who held boy-Emperor Antoku in her arms, drowned themselves together in the sea."
『吾妻鏡』の壇ノ浦の戦いの元暦二年三月二十四日の条で「二位ノ尼は宝剣（天叢雲剣）を持って、按察の局は先帝（安徳天皇）を抱き奉って、共に海底に没する」とある。