Names and extents
Nansei-shotō (南西諸島) is the official name for the whole island chain in Japanese. Japan has used the name on nautical charts since 1907. Based on the Japanese charts, the international chart series uses Nansei Shoto.
Nansei literally means "southwest", the direction of the island chain from mainland Japan. Some humanities scholars prefer the uncommon term Ryūkyū-ko (琉球弧, "Ryukyu Arc") for the entire island chain. In geology, however, the Ryukyu Arc includes subsurface structures such as the Okinawa Trough and extends to Kyushu.
During the American occupation of Amami, the Japanese government objected to the islands being included under the name "Ryukyu" in English because they worried that this might mean that the return of the Amami Islands to Japanese control would be delayed until the return of Okinawa. However, the American occupational government on Amami continued to be called the "Provisional Government for the Northern Ryukyu Islands" in English, though it was translated as Rinji Hokubu Nansei-shotō Seichō (臨時北部南西諸島政庁, Provisional Government for the Northern Nansei Islands) in Japanese.
The name of Ryūkyū (琉球) is strongly associated with the Ryūkyū Kingdom, a kingdom that originated from the Okinawa Islands and subjugated the Sakishima and Amami Islands. The name is generally considered outdated in Japanese although some entities of Okinawa still bear the name, such as the local national university.
In Japanese, the "Ryukyu Islands" (琉球諸島 Ryūkyū-shotō) cover only the Okinawa, Miyako, and Yaeyama Islands, while in English it includes the Amami and Daitō Islands. The northern half of the island chain is referred to as the Satsunan ("South of Satsuma") Islands in Japanese, as opposed to Northern Ryukyu Islands in English.
Humanities scholars generally agree that the Amami, Okinawa, Miyako, and Yaeyama Islands share much cultural heritage, though they are characterized by a great degree of internal diversity as well. There is, however, no good name for the group. The native population do not have their own name, since they do not recognize themselves as a group this size. Ryukyu is the principal candidate because it roughly corresponds to the maximum extent of the Ryūkyū Kingdom. However, it is not necessarily considered neutral by the people of Amami, Miyako, and Yaeyama, who were marginalized under the Okinawa-centered kingdom. The Ōsumi Islands are not included because they are culturally part of Kyushu. There is a high degree of confusion in use of Ryukyu in English literature. For example, Encyclopædia Britannica equates the Ryukyu Islands with Japanese Ryūkyū-shotō or Nansei-shotō in the definition but limits its scope to the Amami, Okinawa and Sakishima (Miyako and Yaeyama) in the content.