The Amami, Okinawa, Miyako, and Yaeyama Islands have a native population collectively called the Ryukyuan people, named for the former Ryukyu Kingdom (1429–1875) that ruled them.

[citation needed] The islands were held by the United States after the 1951 Treaty of San Francisco concluded the Pacific War.

Some humanities scholars prefer the uncommon term Ryūkyū-ko (琉球弧, "Ryukyu Arc") for the entire island chain.

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.

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.

Yanagita hypothesized that the southern islands were the origin of the Japanese people and preserved many elements that were subsequently lost in Japan.

[24][page needed] Based on Ryukyuan folklore on Kudaka Island, some scholars believe that these expeditions succeeded in reaching Japan and launched a social and agricultural revolution there.

The first record of the Southern Islands is an article of 618 in the Nihonshoki (720) which states that people of Yaku (掖玖,夜勾) followed the Chinese emperor's virtue.

An article of 714 reports that an investigative team returned to the capital, together with people of Amami, Shigaki (信覺), and Kumi (球美) among others.

Japan applied to herself the Chinese ideology of emperorship that required "barbarian people" who longed for the great virtue of the emperor.

The New Book of Tang (1060) states at the end of the chapter of Japan that there were three little princes of Yaku (邪古), Haya (波邪), and Tane (多尼).

According to the Nihongi ryaku (c. 11th–12th centuries), Dazaifu, the administrative center of Kyushu, reported that the Nanban (southern barbarians) pirates, who were identified as Amami islanders by the Shōyūki (982–1032 for the extant portion), pillaged a wide area of Kyūshū in 997.

[28] The series of reports suggest that there were groups of people with advanced sailing technology in Amami and that Dazaifu had a stronghold on Kikai Island.

In fact, historians hypothesize that the Amami Islands were incorporated into a trade network that connected it to Kyūshū, Song China and Goryeo.

The Shinsarugakuki, a fictional work written in the mid-11th century, introduced a merchant named Hachirō-mauto, who traveled all the way to the land of the Fushū in the east and to Kika Island (貴賀之島, Kikanoshima) in the west.

The Shinsarugakuki was not mere fiction; the Golden Hall of Chūson-ji (c. 1124) in northeastern Japan was decorated with tens of thousands of green turban shells.

[28] Some articles of 1187 of the Azuma Kagami state that Ata Tadakage of Satsuma Province fled to Kikai Island (貴海島, Kikaishima) sometime around 1160.

The Azuma Kagami also states that in 1188 Minamoto no Yoritomo, who soon became the shōgun, dispatched troops to pacify Kikai Island (貴賀井島, Kikaishima).

[28] The Tale of the Heike (13th century) depicted Kikai Island (鬼界島, Kikaishima), where Shunkan, Taira no Yasuyori, and Fujiwara no Naritsune were exiled following the Shishigatani Incident of 1177.

In 1609, Shimazu Tadatsune, Lord of Satsuma, invaded the Ryūkyū Kingdom with a fleet of 13 junks and 2,500 samurai, thereby establishing suzerainty over the islands.

They faced little opposition from the Ryukyuans, who lacked any significant military capabilities, and who were ordered by King Shō Nei to surrender rather than to suffer the loss of precious lives.

During this period, Ryukyu kings were selected by a Japanese clan, unbeknownst to the Chinese, who believed the Ryukyus to be a loyal tributary.

[37] In 1879, the Meiji government announced the annexation of the Ryukyus, establishing it as Okinawa Prefecture and forcing the Ryukyu king to move to Tokyo.

Some natives of the Ryukyus claim that the central government is discriminating against the islanders by allowing so many American soldiers to be stationed on bases in Okinawa with a minimal presence on the mainland.

Scholars who recognize shared heritage among the native population of the Amami, Okinawa, Miyako and Yaeyama Islands label them as Ryukyuans (琉球人, Ryūkyūjin).

But nowadays, the residents of these Ryukyu Islands do not identify themselves as such, although they share the notion that they are somewhat different from Japanese, whom they call "Yamato" or "Naicha".

Ryukyuan religious practice has been influenced by Chinese religions (Taoism, Confucianism, and folk beliefs), Buddhism and Japanese Shinto.

[citation needed] The south of Watase's Line is recognized by ecologists as a distinct subtropical moist broadleaf forest ecoregion.

[citation needed] The coral-reef related porcelaneous larger foraminiferal species Borelis matsudai Bassi and Iryu, 2023 (Alveolinoidea, Borelinae) is based on specimens discovered in present-day shallow-water sediments from Sekisei Lagoon, southern Ryukyu Islands (Japan).

Other snakes native to the Ryukyus are Achalinus werneri, Achalinus formosanus, Elaphe carinata, Elaphe taeniura, Cyclophiops semicarinatus, Cyclophiops herminae, Dinodon semicarinatum, Lycodon rufozonatus, Calamaria pfefferri, Amphiesma pryeri, Calliophis japonicus, Laticauda semifasciata, and Hydrophis ornatus.