The poetry contained in the volumes extends from the 12th century, or possibly earlier, to some composed by the Queen of Shō Nei (1589-1619).
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Iha Fuyū was among the scholars who traced it to various words associated with oracles and divine songs.
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The first compilation came just after the reign of Shō Shin, who consolidated, centralized, and reformed the government, and the second came just after Ryukyu became a direct vassal to Satsuma.