Ryukyu Islands is the name of the island group between the islands of Kyushu and Taiwan. Ryukyu Islands in Japanese is Nansei Shotō or Ryūkyū Rettō. The northern half is known as Satsunan Shotō, belonging to Kagoshima prefecture, Japan, while the southern half is known as Ryūkyū Shotō, belonging to Okinawa prefecture, Japan.
The Ryukyu Kingdom was a semi-independent kingdom, located between China and Japan. The Chinese government viewed them as a tributary state (and therefore theoretically should come to their aid if necessary). A 1609 expedition from Kyushu captured the island of Okinawa and from then on, the kings of the Ryukyus sent tribute to both China and the Satsuma domain of the Japanese.
In 1879, the Meiji government announced the annexation of the Ryukyus. China objected and the ex-President of the United States Ulysses S. Grant was asked to arbitrate. He decided that Japan's claim to the islands was stronger and ruled in Japan's favor.
Today the Ryukyu islands are collectively Okinawa prefecture. There are a host of problems arising from the Ryukyu's less than completely Japanese history. Some people (a small number perhaps) feel that people from Okinawa Prefecture are not "real" Japanese. Also, some natives of the Ryukyus claim that the central government is discriminating against them by allowing so many American soldiers to be stationed in Okinawa, a far higher percentage than are stationed anywhere else in Japan.
Many popular singers and musical groups come from Okinawa Prefecture. These include (among many others) singer Amuro Namie and the group Da Pump.