The Ryūkyū Kingdom and the Shimazu clan of Satsuma have been engaged in trade for at least several centuries and possibly for far longer than that; in addition, Ryukyu at times had paid tribute to the Muromachi shogunate (1336–1573) of Japan as it has to China since 1372.

One of the chief events which spurs Satsuma to aggression had occurred when Hideyoshi launched the first of two invasions of Korea in 1592.

Through messengers from Satsuma, he had ordered that Ryukyu contribute warriors to the invasion efforts, and was refused; he had also commanded that Ryukyu temporarily suspend its official missions to China.

The mission had traveled to Beijing anyway, on business relating to Shō Nei's formal investiture, and related Hideyoshi's plans to Chinese Court officials there.

Shimazu Yoshihisa, lord of Satsuma, had then suggested that Ryukyu be allowed to supply food and other supplies instead of manpower; Hideyoshi had agreed, but Shō Nei had ignored the related missives.

Following Hideyoshi's death in 1598, and Tokugawa Ieyasu's subsequent rise to power, Shō Nei had been asked by Satsuma to formally submit to the new shogunate, a request which was also ignored.

The Shimazu now requests to launch a punitive mission against Ryukyu and, in 1606, is granted permission by the shogunate.