However, given the fact that Mariko's residence, which was called the Palace of Bamboo, was located on the former estate of the Hiki family in the Hikigatani Valley, her mother was considered to be WAKASA no Tsubone, a daughter of Yoshikazu HIKI.
しかし、竹の御所と呼ばれた鞠子の邸は比企ヶ谷の比企氏の邸跡である事から、母は比企能員の娘若狭局と考えられる。