3. Early Mentions of Ryukyu and Amami
The first mention of a Ryukyu-koku, or Country of Ryukyu, is from Sui Dynasty era China (CE 581-618). There is mention of an “island country located in the East China Sea which can be reached by sailing for five days” in the official history of the era the Sui Shu [隋書] (compiled between CE 636-656).
Based on this and on more detailed descriptions of the region there was disagreement among scholars on the precise location Ryukyu-koku referred to, whether Okinawa or Taiwan (Footnote 1). As Sakihara Mitsugu wrote of the confusion, there are passages in the Sui Shu mentioning knives, bows, arrows and swords that could equally refer to both Taiwan and Okinawa while others seem specific to Taiwan or Okinawa individually (Footnote 2). Even Portuguese visitors to the region in the early 16th century were confused about the name (Footnote 3) and solved the problem by marking Taiwan on maps as Llequio Pequeno (Little Ryukyu) and Okinawa as Lleqio Grande (Big Ryukyu).
The reason for the discovery of either Taiwan or Okinawa was that between 607-610 Emperor Yangdi [煬帝] dispatched expeditions from the Yian province led by military commanders to investigate populated areas in thus far unexplored areas. Commander Zhu Kuan [朱宽] may have been the one to come up with the name Liuqiu [流求], or perhaps not. Regardless, over time the name Ryukyu did come to pertain to the islands of Okinawa and, eventually, the entire archipelago that includes the island groups of Amami, Okinawa, Miyako and Yaeyama.
With regard to specific locations within the Ryukyu archipelago appearing in the historical records of another country, Amami [奄美] is first mentioned in the 'Shoku Nihongi (one of the so-called ‘Rikkokushi’ or ‘Six National Histories of Japan [六国史]’),' an 8th century official Japanese history text (Footnote 4). During the 7th century, envoys from the Yamato Court [大和朝廷] were sent to Tang Dynasty China from which political systems and multiple aspects of culture were acquired and then adopted. Envoys from Japan would sometimes pass near to the northern Ryukyus en route to China, hence mention of Amami (Footnote 5). Where the story starts to get muddy is when it comes to the nature of relations between Amami and the Yamato Court. According to the Rikkokushi, envoys from the Ousumi [大隅] and Amami islands had paid official visits to the Court. According to the keepers of Japanese history this is when gifts received were regarded as tribute and, therefore, when these areas became vassals. The Amamian perspective, of course, is different. It was not tribute that was being paid but simply gifts to cement friendship and develop trade avenues. History is surely riddled with cases of gifts mistakenly regarded as tribute. As national histories are compiled it looks altogether better prestige-wise for the state to extend its territorial boundaries to include areas regarded as vassals or tributaries. It’s like adding a splash of make-up to look good under the lights on TV.
Footnotes for 1-3. Early Mentions of Ryukyu and Amami
(Footnote 1) Liang Chia-pin, "On the “Liu-ch'iu” in the Sui-Shu", Chinese Culture Vol. 10, No. 1, March 1969. If you can acquire this it is an interesting read on the issue of whether Liuchiu actually referred to Okinawa or Taiwan.
(Footnote 2) Sakihara Mitsugu, ‘History of Okinawa’ in Ethnic Studies Oral History Project, United Okinawan Association of Hawaii, Uchinanchu, A History of Okinawans in Hawaii (Honolulu: Ethnic Studies Program, University of Hawaii at Manoa , 1981), page 6.
(Footnote 2) In the 2001 edition of Arashiro Toshiaki's 高等学校琉球・沖縄の歴史と文化 a Japanese rendering of the original Chinese text of the Sui Shu pertaining to Taiwan or Okinawa is presented on page 22.
(Footnote 3) Portuguese map from: メンデス・ピント著 (岡村多希子訳), 東洋遍歴記 (トウヨウ ヘンレキキ) Peregrinação. 東京 : 平凡社 , 1979-1980. .
(Footnote 4) http://ja.wikipedia.org/wiki/六国史
(Footnote 5) 新城俊昭 (Arashiro Toshiaki), 高等学校琉球・沖縄の歴史と文化 : 書き込み教科書 (糸満 : 編集工房東洋企画, 2010).
Further References for 1-3. Early Mentions of Ryukyu and Amami
By far the most comprehensive resource covering the etymology of both 'Ryukyu' and 'Okinawa' is Kodama Masato's award-winning book from 1993: 小玉正任、史料が語る琉球と沖縄 (Shiryou ga kataru: Ryuukyuu to Okinawa. Ryukyu and Okinawa: As Mentioned in Historical Sources). 東京: 毎日新聞社、1993.
Supplementary Material: An Overview of Ancient Amami (Translated from Hamada Keisuke's Amami no Rekishi [浜田敬助, 奄美の歴史. 大井町(埼玉県 : 浜田敬助 , 1987, pages 204-208])
613 - At this time people from (掖玖人- today 屋久島人（やくしまじん)) Yakushima coming and going between the southern islands and Japan.
824 - Southern Islands fell under the jurisdiction of the Dazaifu (太宰府). Nominally aligned with Osumi-kuni (大隅国), but independent in reality
1372 - The king of Ryukyu, at the invitation of the Ming Emperor (太祖), established the country as a trading state.
1368 - The Ming Dynasty banned overseas maritime trade voyages and expeditions.
1404 - Ashikaga Yoshimitsu received preferential trading status (in the form of a kankoufu [勘合符]) from the Ming Emperor.
1429 - The King of Chuzan defeated Nanzan and Hokuzan to unify Okinawa Island.
1466 - The Ryukyu King Sho Toku conquered Kikai Island with 2,000 troops and 50 warships.
1480 - Ashikaga Yoshihisa sent a letter to Shimazu urging him to supervise Ryukyuan ships and have the Ryukyu King send tribute to Kyoto.
1516 - The Lord of Bittchuu no Kuni [備中の国] (located in present day Okayama prefecture), Miyake Izuminokami Kunihide, challenged Shimazu’s right to supervise Ryukyuan shipping, sending a task force to Naha. Shimazu Tadaharu got wind of the plan, killed Miyake and destroyed his 12-ship force.
1536 - Satsuma’s chief retainer informed that Miyake Kunihide’s [二宅国秀] faction will probably launch another attack on Ryukyu.
1537 - King Sho Sei of Ryukyu attempts the conquest of Amami Oshima.
1547 - This was the final year of Japan-Ming preferential trading.
1571 - King Sho Gen of Ryukyu conquers Amami Oshima.
1582 - Kamei Korenori of Kishi [紀州の亀井玄矩] was given possession of Ryukyu by Toyotomi Hideyoshi. Kamei sets out for Ryukyu with an expeditionary force to claim his gift.
1606 - Shimazu Iehisa is given permission to conquer Ryukyu by Tokugawa Ieyasu.
1609 - Satsuma forces launch an invasion into Ryukyu. Fighting takes place throughout the islands of Amami. The Ryukyu King Sho Nei is captured and interned.