In the sixth year of Empress Saimei, Paekche was destroyed by the allied armies of Tang and Silla. Kwisil Poksin, a loyal minister of Paekche, sent envoys asking to receive Prince Pung, then a hostage in Japan, as their king, and requested an army to help them. The empress said, "To help a nation in peril and to restore a nation that has fallen is right," and decided to send aid.
On the sixth day of the first month of the seventh year, the imperial ship set out west, taking the sea road for the first time. On the eighth day, when it reached the sea of Oku (near Oku in Okayama), Princess Ota, who was traveling with the court, gave birth to a girl, and so the child was named Princess Oku.
On the fourteenth, the imperial ship anchored at the Ishiyu Palace at Nikitatsu in Iyo. Ishiyu is today's Dogo hot spring. The empress's company stayed there for some time, waiting for the right tide and wind. The poem in the Man'yoshu, "At Nikitatsu, as we wait for the moon to board our ships…", said to be by Princess Nukata, is traditionally linked to this departure.
On the twenty-fifth of the third month, the ship returned to its course, reached Na-no-Otsu (Hakata Bay) and entered the Iwase Palace. The empress renamed the place Nagatsu. In the fifth month she moved to the Asakura Tachibana-no-Hironiwa Palace, but because trees of the Asakura shrine had been cut down to build it, the thunder god in his anger wrecked the hall, will-o'-the-wisps appeared in the palace, and many attendants fell ill and died.
On the twenty-fourth of the seventh month, the empress died at the Asakura Palace. In the eighth month the crown prince (Naka-no-Oe) went into mourning and returned to the Nagatsu Palace. That evening a demon in a great broad hat appeared on Mount Asakura and watched the funeral rites, and everyone thought it strange.