Sanzan period

The Sanzan period (三山時代, Sanzan jidai; lit. 'three mountain period') is a period in the history of the Okinawa Islands when three lines of kings, namely Sanhoku (山北; lit. 'north of the mountain (island)'), Chūzan (中山; lit. 'middle mountain (island)') and Sannan (山南; lit. 'south of the mountain (island)'), are said to have co-existed on Okinawa Island. 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. Historical records of the period are fragmentary and mutually conflicting. Some even question the co-existence of the three polities.

Okinawa does not have their own contemporary records of the Sanzan period. Contemporary sources are limited to Chinese and, to a far lesser extent, Korean diplomatic records. They are in a fragmentary fashion and probably overshadowed by diplomatic fictions. Since the Chinese sources simply record local rulers who contacted China, they do not rule out the possibility that some other local rulers co-existed without establishing diplomatic contacts. For this reason, Okinawa's real situation remains largely a mystery.

According to the Veritable Records of the Ming, the newly formed Ming dynasty sent an envoy to what it called the "State of Ryūkyū", among many other countries, in 1372 to start tributary relations. In response, a ruler who was referred to as Satto, King of Chūzan, sent his younger brother Taiki to pay tribute. In 1380, Shōsatto, King of Sannan, sent a mission to Ming China, which was followed by Hanishi, King of Sanhoku in 1383. The names of Sanhoku and Sannan are apparently Chūzan-centric. It is not clear who coined these names.

Ming China's perception of the co-existence of the three "kings" can be found in an article of 1383 of the Veritable Records, which was based on the report of a Ming envoy who visited Okinawa in 1382. The Ming considered that there were three rulers in the region who engaged in conflict. It recognized them as "kings" and called for peace.

As for the Kings of Sanhoku, the Veritable Records record the un-Okinawan-looking names of three kings, Hanishi, Min and Han'anchi, but make no mention of their blood relations. The last diplomatic contact of the King of Sanhoku was of 1416.

The records of the Kings of Sannann are more complicated. The diplomatic missions under the name of Shōsatto, King of Sannan, lasted from 1380 to 1396. 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 1403, Ōōso, who claimed to be Shōsatto's younger brother or cousin, reported Shōsatto's death in 1403 and was recognized as King of Sannan the next year. In 1415, Crown Prince Taromai reported that King Ōōso had been murdered by his "elder brother" Tafuchi. Taromai's blood relationship with Ōōso was not mentioned. As the King of Sannan, Taromai sent envoys from 1416 to 1429.

The Annals of the Joseon Dynasty of Korea records mysterious events about the King of Sannan. In 1394, Satto, King of Chūzan, requested Korea to return Shōsatto, Crown Prince of Sannan (山南王子承察度), who had supposedly fled to Korea. In 1398, Onsadō, King of Sannan (山南王温沙道), fled to Korea after reportedly being banished by the King of Chūzan. He died there in the same year. These records clearly contradict the Veritable Records, raising questions about the reliability of Okinawa's diplomatic correspondence to foreign countries.

The King of Chūzan sent envoys to China much more frequently than the Kings of Sanhoku and Sannan. The King of Chūzan paid tribute biennially from 1372 to 1382 and after that once or twice a year. Chūzan's missions were also unusual in that some of them were sent under the name of the crown prince although it should have been done by the king. In 1404, Crown Prince Bunei reported King Satto's death and was recognized as the next king. 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.