Sanzan period
It is said to have started during King Tamagusuku's reign (traditional dates: 1314–1336) and, according to Sai On's edition of the Chūzan Seifu (1725), ended in 1429 when Shō Hashi unified the island.
In response, a ruler who was referred to as Satto, King of Chūzan, sent his younger brother Taiki to pay tribute.
An unusual characteristic of Sannan was that the "King's father's younger brother" (王叔) Ōeishi also sent envoys from 1388 to 1397.
In 1415, Crown Prince Taromai reported that King Ōōso had been murdered by his "elder brother" Tafuchi.
In 1407, Crown Prince Shishō's envoy reported his "father" Bunei's death to seek the approval of the succession to the throne.
An article of 1425 in the Veritable Records states that Ming China let Crown Prince Shō Hashi succeed the late King Shishō.
[1][2][4][5] The Annals of the Joseon Dynasty states that in 1418, Katsuren, the second son of the King of Chūzan, called for trade with Korea and sent vessels that carried Chinese and Southeast Asian goods.
The only thing that can be inferred from the records is that the Kings of Sanhoku and Sannan ceased to send diplomatic missions.
Sai On, in particular, extensively rewrote his father's edition of the Chūzan Seifu using newly obtained Chinese sources.
[6] Additionally, the Omoro Sōshi (1623) is helpful in understanding Okinawa's own world-view although it is a compilation of poems and by no means a history book.
For some unknown reason, however, Sai On changed the names of Sanhoku and Sannan to Hokuzan (北山) and Nanzan (南山) respectively.
[7] According to Ryūkyū's official history books, King Tamagusuku, who had maintained a unified polity, lost the support of local rulers.
Most modern historians question this alleged split because they do not support the existence of a unified polity on Okinawa before the "reunification" in the 15th century.
Sai On's edition of Chūzan Seifu adds two personal names, Min and Han'anchi, which were taken from a Chinese source, not from Okinawa's own.
The names of Ōōso and Taromai, added by Sai On to the Chūzan Seifu, are not based on Okinawa's own narrative.
The Chūzan Seifu identify the Shimasoe-Ōzato Aji as the King of Sannan, which appears to reflect Okinawa's own narratives.
[3] According to the Chūzan Seikan, the Aji of Nakijin's domain included Haneji, Nago, Kunigami, Kin, Ie and Iheya.
The Aji of Ōzato controlled the 11 regions of Sashiki, Chinen, Tamagusuku, Gushikami, Kochinda, Shimajiri-Ōzato, Kyan, Mabuni, Makabe, Kanegusuku and Tomigusuku.
The Chūzan King subjugated Naha, Tomari, Urasoe, Chatan, Nakagusuku, Goeku, Yomitanzan, Gushikawa, Katsuren and Shuri.
However, it is clear from literary evidence and archaeological findings that Urasoe was the center of the most powerful polity on the island before the capital was moved to Shuri.
After Seii's death, people deposed the crown prince and enthroned Satto, the ruler of Urasoe, in 1350.
Although his existence was supported by contemporary sources, his life is colored by mythology: he was a son of a humble farmer and a swan maiden.
[3] Although the history books agree that Shō Hashi unified Okinawa, the accounts of the unification process contain non-negligible inconsistencies.
The oldest Chūzan Seikan states that after Shō Hashi succeeded his father Shishō as Aji of Sashiki in 1402, he overthrew the King of Sannan and claimed the title.
From these records, Sai On naïvely inferred that these two kings ceased to exist immediately after the last contacts.
In order to maintain international trade that covers the vast area from Southeast Asia to Japan and Korea, they set up tribute-paying missions under the names of foreign kings.
