“The Fourangle Number Indexing System for Chinese Characters”was introduced by Gao Mengdan and completed by Wang Yunwu. This indexing system for Chinese characters has nothing to do with GuoYin Code invented by Zhang Yusheng. Wang Yunwu undoubtedly made an important contribution to improving and implementing “The Fourangle Number Indexing System for Chinese Characters”and the publishing of “The Fourangle Number Dictionary”.