Xu Shen
Xu Shen placed approximately 13% of characters in this category, but many of his examples are now believed to be phono-semantic compounds whose origin has been obscured by subsequent changes in their form. Peter Boodberg and William Boltz go so far as to deny that any of the compound characters devised in ancient times were of this type, maintaining that now-lost "secondary readings" are responsible for the apparent absence of phonetic indicators, but their arguments have been rejected by other scholars.