The Yuan, Ming and Qing emperors of China intermittently sent diplomatic missions to Shuri, Okinawa, in the Ryukyu Islands.
Upon the accession of a new king, the news was generally communicated to the Chinese capital, along with a petition for the investiture, by a formal Ryukyuan tribute mission.
Following the 1609 invasion of Ryukyu, beginning with the succession of Shō Hō, the Satsuma Domain also had to be notified and asked for approval and confirmation of the new king.
[1] Chinese envoys would then be dispatched - sometimes quite quickly, sometimes not until over a decade later - arriving in ships called ukwanshin (御冠船, lit.
During Japan's Edo period, an agent from Satsuma known as a kansen bugyō (冠船奉行, "investiture (crown) ships magistrate") would be sent down to Ryukyu to supervise the exchanges and interactions between Chinese and Ryukyuan officials, albeit from somewhat of a distance, given the policy of hiding Satsuma's involvement in Ryukyu from the Chinese.