The Ryukyu Kingdom was one of the important trade hub in South China Sea. The trading between the kingdoms in East Asia and South-East Asia could run smoothly because, Okinawa island locates between the mainland China, Taiwan, The Philippines archipelago and Kyushu island of Japan. Okinawa island became a port city for these trade ships, made the Ryukyu kingdom wealthy by collecting port tax and also trade with the other realms to spread the local goods.
In the year of 1609 AD, the Tokugawa Shogunate ordered the daimyo of Satsuma domain (Present day Kanagawa prefecture) to lead the invasion force of Ryukyu kingdom and succeeded. This caused the kingdom to become a tributary state of both China and Japan.
To avoid being noticed by the Ming dynasty that the Ryukyu kingdom was conquered by Japan. The shogunate must treat the Ryukyuan as foreigners and forbade them to do many things such as do not dress like the Japanese, do not use Japanese name, do not learn Japanese language and do not practice any Japanese culture. Aside from that, the Ryukyuan could not travel to Japan and the Japanese could not travel to Ryukyu kingdom without Shogun's permission.
The Shimazu clan, the daimyo of Satsuma domain which was the only one that had the kingdom as their vassal. They were granted the right to bring the Ryukyuan king with them when they had the official visit to capital city. When they march into the castle, the ryukyuan made the Shimazu parade distinguished from the other like they were not from Japan.
ทหารริวกิวทำการป้องกันเมืองจากผู้รุกรานชาวญี่ปุ่น The Ryukyuan soldiers defending the city from the Japanese.