Criticisim of Two Cycles & Eight Periods AND Xuan Kong Liu Fa (3)

1. Introduction

If we want to make a judgment whether the above principle is true or not, we must confirm the elements and basic of this principle as follows:

1. The principle of 2 cycles and 8 periods (二元八運) uses Yang Yao (陽爻) (solid line of a trigram or bagua 八卦) represent 9 years while Yin Yao (陰爻) (divided line of a trigram) represent 6 years. But why only the time unit: “Year” is chosen?
   
2. The introduction of calculation by using 2 cycles & 8 periods is tabulated as follows:

Table 1. The introduction of calculation by using 2 cycles & 8 periods.

Period	Later Trigram in Palace (Hou Tian Gua 後天卦)	Early Trigram (Xian Tian Gua 先天卦)	Line (Yao 爻) from Early Trigram	Govern (Years)
1st	Kan 坎	Kun 坤	3 yin	18
2nd	Kun 坤	Xun 巽	2 yang & 1 yin	24
3rd	Zhen 震	Li 離	2 yang & 1 yin	24
4th	Xun 巽	Dui 兌	2 yang & 1 yin	24
The above is the Upper Cycle in which 90 years are included.
6th	Qian 乾	Gen 艮	2 yin & 1 yang	21
7th	Dui 兌	Kan 坎	2 yin & 1 yang	21
8th	Gen 艮	Zhen 震	2 yin & 1 yang	21
9th	Li 離	Qian 乾	3 yang	27
The above is the Lower Cycle in which 90 years are included
The 8 periods totally have 180 years.