The sima nö miya “Island Palace”, was an estate originally belonging to Soga no Umako (d. 626), a major power behind the throne in Yamato Japan. Following his death, it passed into the hands of the Imperial clan and was used as a detatched palace. Its was situated near the banks of the Asuka River, but not on an actual island, so the imagery used the guards’ poems is poetic conceit and not literal description.

Kusakabe was the son of Emperor Temmu (d. 686) and the redoutable Uno no Sarara (645 – 702). She cleared the way for Kusakabe’s appointment as Crown Prince by eliminating Prince Ōtsu, Temmu’s son by her sister, who was forced to commit suicide a month after his father’s death. When Kusakabe died in 689, his mother assumed the throne herself, and ruled as Empress Jitō (690 – 697).