Contrary to the file name, this image is not attested in Ryukyu Kingdom period sources. A flag of the Ryukyus that was created by the United States Civil Administration of the Ryukyu Islands in 1954 but was never officially adopted. It also appeared in a Japanese novel titled "Ryūkyū shigeki: Tomoebata no akebono" (1946) by Yara Chōchin.
Drawn in Macromedia Fireworks and converted to SVG in Adobe Illustrator by User:Jecowa.
Jecowa