The correlation of the luoshu numbers and bagua trigrams is the minimum requirement for conducting bazhai fengshui readings. A formula called the da you nian, “Great Roving Year” is the means by which number and trigram merge. First, the sequence of digits 1 through 9 is repeated 20 times to match three sixty-term, ganzhi cycles of 180 years called the sanyuan, “Tri-epoch.” Since every year has a ganzhi designation, in the Tri-epoch everyone’s year of birth has a digital correlate from 1 to 9. Each luo number has a unique trigram, derived from its houtian correlation (see fig. 2), so when the Tri-epoch digit is equated with the luo number, each person has a trigram that corresponds to his/her natal year. This is called the minggua, or the natal trigram, and it identifies the character of cosmic qi present at the person’s birth. Finally, the natal trigram is paired with each of the eight directional trigrams in the houtian sequence (called zhaigua or hall trigrams). Each of the eight minggua therefore has a corresponding eight zhaigua, and these eight groups of eight trigrams complete the da you nian. This complement of a natal trigram and its set of hall trigrams represents a metaphysical interaction between the individual’s natal qi and the qi of the environment that surrounds that individual. This conjunction is essentially thought of as a transformation of the minggua into the zhaigua and vice-versa (called biangua or bianyao), and each transformation is capable of generating good or bad fortune for the individual. The auspice generated by the conjunction is known as jiuxing, or the Nine Stars.