Kyushu, seeking to defend against a possible Sino-Korean invasion, and integrated provincial elites into the court rank system. These efforts increased royal authority, but created considerable unrest among the Japanese clans.

Oama's first wife was Princess Nukata, the daughter of an obscure noble named Prince Kagami. Oama also married four of Naka's daughters, likely as an effort to lessen the influence of prominent families such as the Soga over future successors. Among these was Uno-no-sarara,