The Shimazu clan of the Japanese feudal domain of Satsuma invaded the kingdom during the 1609 Invasion of Ryukyu . Satsuma was able to capture Shuri Castle and King Shō Nei by early May , then sent a message to the Sakishima Islands demanding their surrender , which they complied with . In the following centuries of vassalage to Satsuma , the Ryukyuan government was placed under extreme tax pressure , and instituted a heavy poll tax in the Sakishima Islands . As a result of the extreme economic conditions , infanticide and other methods of population control became common , as they did throughout the Ryukyu Islands ; remains of the sites where this took place can still be found throughout the Sakishima Islands . Yaeyama islanders were taxed even more heavily than those of Miyako , as the rebel Oyake Akahachi was from Yaeyama . The kingdom prohibited migration of islanders , isolating them to prevent group resistance . The Yaeyama earthquake in 1771 caused a tsunami which killed 12,000 , or a half of the entire Sakishima population . Because the soil was adversely affected by salination , famines were frequent , and the population of the islands further decreased until the early Meiji period
Yaeyama earthquake
1771 Great Yaeyama Tsunami
Sakishima Islands