清华简《筮法》筮数的三种可能演算

Three Possible Kinds of Calculation of the Divinatory Numbers in the Shifa on the Tsinghua Bamboo Slips

使用五十六或五十七或五十八根蓍草,在按照《系辞上》大衍筮法"一变"前的步骤,经过"五变"的前提下,可以得出清华简《筮法》筮数九、八、七、六、五、四。六个筮数中,其出现概率规律是,六和七最多,约占三分之二,五和八次之,四和九最少。《筮法》第一至十九节228个三画卦中六个筮数出现频率情况,与其出现概率规律有相同处,也有不同处。这是由于《筮法》筮例的选择性,影响了对筮数概率规律的充分表达。

Using fifty-six, fifty-seven, or fifty-eight milfoil stalks and manipulating them by the “Great Expansion” method introducedin the Xici （Commentary on the Appended Phrases） through “five changes”, one can obtain the divinatory numbers of 9, 8, 7, 6,5, and 4. Among them, 6 and 7 are most frequently occurred, occupying about 2/3, while the possibility of occurrence of 5 and 8takes the second place, and 4 and 9 occur the least. The frequency of the occurrence of the six numbers in the two hundred twenty-eight trigrams in the Shifa is not completely commensurate with the above-mentioned possibility of occurrence in that the selection ofthese cases affected an adequate manifestation of the possibility.