The term chóngniǔ 重紐, literally “repeated initial consonants”, refers to situations where certain rhymes (=rimes) in the Middle Chinese rhyming dictionaries of the Qièyùn 切韻 tradition (Traditional Chinese phonology) include separate homophone groups that seem to have the same initial consonant (based on fǎnqiè 反切 spellings and on placement in the rhyme tables), which cannot be distinguished as kāikǒu 開口 versus hékǒu 合口, and which the later rhyme-table tradition distinguished by placing one in the third row of the tables (sānděng 三等) and one in the fourth row (sìděng 四等). The syllab…