this writing style can alternatively be seen as Written Okinawan with heavy interference from Written Japanese. Nevertheless, it was markedly different from any spoken register of the day. Another genre where this writing style was adopted was letters of appointment. In the famous Dana Documents, a collection of appointment letters preserved by a samurai family, the first appointment letter dated 1523 reads: In the document, the king appointed Shiotarumoi as a member of Takara-maru, a ship designated for a tributary mission to China. Although Okinawan flavor is non-negligible, the phrase tamawari mōshi sōrō (an honorific form of "to be given by the king's order") is a distinctive characteristic of sōrō-style Japanese. Apart from lexical and grammatical features, a notable characteristic as a writing convention is the ratio of kana in relation to kanji. Kanji appeared very infrequently, and the number of unique kanji in the corpus is less than a hundred. This Old Ryūkyū-style writing disappeared after the conquest of the kingdom by Satsuma Domain in 1609. Shift to standard sōrō-style Written Japanese Under Satsuma Domain, the style of appointment letters shifted to standard sōrō-style Written Japanese. The relative frequency of kanji remarkably increased during a transitional period. An example from the transitional period is the 12th appointment letter from the Dana Documents (1627): In the end, kana disappeared from appointment letters: Although this letter was written completely with kanji, it was read aloud as sōrō-style Japanese. This writing convention was used in local administrative documents and correspondence between Ryūkyū and Satsuma. Except for the use of Chinese era names, the local administrative documents were no different from those produced in other domains under the Tokugawa shogunate. Recordings of oral performance The Omoro Sōshi (1531–1623) was the first systematic attempt to record songs. The song at the very beginning of the anthology, for example, was: The first line specifies the melody (the melody of Aoriyae) while the special characters "一" (start) and "又" (repeat) are used for flow control. Kana was chosen to precisely record the oral tradition. Only 51 unique kanji were used in the song part of the Omoro Sōshi. Some songs were accompanied by notes that were written in Written Japanese. Because the Omoro Sōshi was enigmatic even to the Okinawan elites of the day, a dictionary named Kon-kōken-shū was compiled in 1711, where each archaic word is described in Written Japanese, with extensive references to Japanese