Xu Shen
To organize the thousands of headwords, Xu Shen established 540 radicals, and ordered them from least to greatest complexity. Each radical then headed its own group, which in turn subsumed all composite characters which incorporated the specific radical. The total number of 540 has a cosmological weight, as it can be derived from the product of 6, 9, and 10. 6 and 9 are the numbers of Yin and Yang, and 10 a number signifying completion. This number symbolizes the exhaustive scope of the dictionary.