In the Classic of Poetry,there are thirteen examples of Bu(不)and Wu(無) with pronunciation but without meaning,which constantly impelled many experts of the various schools to hold different views on its annotations.
《詩經》中“不”字和“無”字共有762例,據統計,它們的意義沒有被前人確定下來的有39例,經分析其中的13例“不”和“無”有音無義(其余的26例“不”和“無”还有待確定)。