Shō Nei Shō Nei was the great - grandson of Shō Shin ( 尚真 , r . 1477 – 1526 ) and the adopted son - in - law of Shō Ei ( 尚永 , r . 1573 – 1586 ) . Biography . Early in Shō Nei ' s reign , Japanese warlord Toyotomi Hideyoshi planned an invasion of Korea . Through messengers from Satsuma , he ordered that the kingdom contribute warriors to the invasion efforts , and was refused ; he also commanded that Ryukyu temporarily suspend its official missions to China . The mission traveled to Beijing anyway , on business relating to Shō Nei ' s formal investiture , and related Hideyoshi ' s plans to Chinese Court officials there . A short while later , Shō Nei sent a missive to Hideyoshi , as was customary upon the installation of a new ruler . He formally congratulated Hideyoshi on having taken over Japan , and on bringing peace and prosperity to the realm , and sent along with the missive a gift of Ming Chinese lacquerware . The letter referred to Ryukyu as a " small and humble island kingdom < nowiki > [ which ] < / nowiki > , because of its great distance and because of lack of funds , has not rendered due reverence to you . " Shimazu Yoshihisa , lord of Satsuma , then suggested that Ryukyu be allowed to supply food and other supplies instead of manpower . Hideyoshi accepted this proposal , but Shō Nei ignored it , and sent no supplies . Following Hideyoshi ' s death in 1598 , and Tokugawa Ieyasu ' s subsequent rise to power , Shō Nei was asked by Satsuma to formally submit to the new shogunate , a request which was also ignored . Satsuma invaded Ryukyu in the beginning of 1609 , and Shō Nei surrendered on the fifth day of the fourth lunar month . Shō Nei was taken , along with a number of his officials , to Sunpu to meet with the retired Shogun Tokugawa Ieyasu , then to Edo for a formal audience with Shogun Tokugawa Hidetada , and then to Kagoshima , where he was forced to formally surrender and to declare a number of oaths to the Shimazu clan . At Edo , the shogun stated that Shō Nei should be allowed to remain in power due to the long history of his line ' s rule over the islands . This marked the first time the ruler of a foreign country had come to Japan , and Shimazu Tadatsune , the lord of Satsuma , made sure to take advantage of the political value of the occasion for himself . His successors would continue to make use of their status as the only " daimyō " to have a foreign king as a vassal to secure for themselves greater political privileges , stipends , and court ranking . In 1611 , two years after the invasion , the king returned to his castle at Shuri once Tadatsune and his advisors were satisfied that he would uphold the oaths he had sworn . Though Satsuma initially exercised a strong hand in declaring policy in Ryukyu , and purging the royal government of those perceived as disloyal to Satsuma , by 1616 this approach came to an end . " Japanization " measures were reversed , at the request of Satsuma , and Shō Nei was once more formally granted primacy over his kingdom . For the remainder of his reign , Shō Nei would continue to bear all the trappings of royal authority , and exercised great power over his domain within the frameworks set by Satsuma . Upon his death , Shō Nei was buried not in the royal mausoleum at Shuri , but rather at Urasoe Castle . Popular belief says this is because he felt that by succumbing to Satsuma ' s invasion , he had deeply dishonored himself before his ancestors , and was unfit to be buried with them . However , Shō Nei was originally from Urasoe , so a more mundane explanation may be the truer one . The Oaths Sworn . Shō Nei was forced to swear a number of oaths during his time in Kagoshima , as he and his kingdom were formally made vassals to the Shimazu clan . The so - called Fifteen Injunctions ( 掟十五ヶ条 , " Okite jūgo - ka - jō " ) were among the most major , and primarily involved political and diplomatic matters . These stated , among other stipulations , that Ryūkyū would not engage in trade or diplomatic relations with foreign states without the consent of Satsuma . These policies , along with maritime restrictions and other stipulations , would govern Ryūkyū ' s domestic situation and foreign relations for over 250 years . Shō Nei and the members of his Council of Three were also required to swear that the kingdom had long been a dependency of Satsuma ( a falsehood ) , and that they acknowledged that their failure in recent years to live up to their obligations to Satsuma had brought this invasion , a punitive measure , upon themselves . The oath went on to acknowledge the benevolence of Satsuma in allowing the king and his councillors to return to their kingdom , and to continue to rule . Shō Nei swore to pass on these oaths to his descendants , further ensuring the relative permanence of the vassal - lord relationship into which Ryūkyū had been entered with Satsuma .