On the other hand, although not the real mother of the crown prince but an empress or princess who fostered the crown prince as an adoptive mother or a woman who played the role of his mother is titled 'junbo' (a woman who was given the status equivalent to the emperor's birth mother).
また、天皇の生母ではないが、養母として天皇の養育にあたった后妃や、母に準ずる存在に擬せられた女性を「准母」という。