元史
These episodes cannot be found in the "Chūzan Seikan" (1650) or Sai Taku's edition of the "Chūzan Seifu" (1701). In fact, it was Sai On who copied them from Chinese sources. Modern scholars generally consider that the Liuqiu (瑠求) in the Chinese sources referred to Taiwan, not Okinawa Island. In fact, the "History of Yuan" states that the Penghu Islands and Liuqiu faced each other and that the envoys of 1292 visited Penghu en route to Liuqiu.