[Certificate issued on 8th moon of Sho Toku (Cheng Te) 4 (Sept 2, 1509)]

Sho Shin, King of the Ryukyu Country Chuzan, in reference to the tribute and related matters, is deeply concerned over the circumstance that this country's products are meager and inadequate as articles of tribute, causing great inconvenience. For that reason, we are now despatching Chief Envoy Kamadu, Interpreter Ko Ken (Kao Hsien), and others aboard a seagoing ship bearing the designation of the character Ko (K'ang), which a cargo of porcelain and other goods, to proceed to the productive land of Malacca in order to purchase such products as sapanwood and pepper through mutually satisfactory arrangements, and then to return to this country to make preparations for the presentation of tribute to the Ming Celestial Court in a subsequent year. However, the members of the mission now departing do not have official credentials individually and are indeed fearful of the inconvenience of investigations and obstructions by officials along the way. So the Royal Court has issued a Certificate stamped with a split seal bearing the character Gen (Hsuan) and the number 174, to be received and borne by Chief Envoy Kamadu and others in proceeding on their mission. Accordingly, it is requested that officials and guards of the straits and coastal waters will, after examining this Certificate, release them promptly and not inconveniently deter them from proceeding on their way. This Certificate is hereby bestowed. It is now stated (that the mission comprises): One chief envoy - Kamadu; two assistant envoys - Maniku and Gurami; two interpreters - Ko Ken (Kao Hsien) and Ko Ka (Kao Ho); pilot Ryo Mi (Liang Shih); general manager of the ship - Mafutu; lesser officials and crew - 150 persons.

Shunzo Sakamaki `Ryukyu and Southeast Asia’ Journal of Asian Studies (1964) 23: 383-90, p. 386

Few Japanese were permitted to the go to the islands, and among them only the officials could establish residence there. Whenever foreigners arrived, all Japanese were instructed to seclude themselves. On the rare occasions when they accompanied Ryukyu ships to China, they assumed names and manners of the islanders to avoid identification as Japanese. For Ryukyuans voyaging to China, a secret guidebook, Ryyokonin kokoroe ("Things for Travelers to Bear in Mind"), usually attributed to the famous scholar-official Sai On (1682-1763), instructed them on how to parry questions about Sastuma-Ryukyu relations. If asked about the mony and goods on the ships (much of Satsuma origin) they were to reply that they were from Takarashima ("Treasure Island").