KokumoKokubo (imperial mother) (国母)

Kokumo (or Kokubo) is the title for real mothers of emperors or kings.

As Shokugensho tsuko (Consideration on "Shokugensho" [history of governmental post]) describes 'Kokumo is the real mother of the reigning emperor', 'Kokumo' does not indicate the status of the Emperor's lawful wife as the Empress and the Empress Dowager; rarely though, 'Kokumo' is improperly used for the Empress Dowager.

The word of 'kokumo' first appeared in an article of "Veritable Records of Three Reigns of Japan" (Nihon Sandai Jitsuroku), dated on March 25 of the third year of the Gangyo era which says 'empress to Emperor Junna demised. On that day, Kokumo made a call of condolence' when the empress to Emperor Junna, Imperial Princess Masako passed away.

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).

FUJIWARA no Senshi, the real mother of Emperor Ichijo, became a nun and entitled Higashi Sanjoin, which set a precedent for kokumo and Junbo to become nun and then entitled nyoin (a close female relative of the Emperor or a woman of comparable standing). At later times, there were cases of exception where the title nyoin was given to kokumo or junbo who did not become a nun, or even to those who were not kokumo or junbo.

After the Meiji Restoration, the title of kokumo has not been used.