be based on Song dynasty rime dictionaries, particularly the Lǐbù yùnlüè (禮部韻略, 'Rimes of the Ministry of Rites') issued by the Ministry of Rites in 1037...

Libu Yunlüe (壬子新刊禮部韻略) divided common Chinese characters in poetry into 107 rhyme categories. However, in 1223, Xinkan Yunlüe (新刊韻略) was already published...