An ancient script says:
"When sky (heaven) is not at right time,
sun and moon do not show their shine.
When land (earth) is not at right time,
everything does not grow alive.
When sea (water) is not at right time,
wind and wave are not calm.
When human is not at right time,
good, smooth and prosperious ways are
not accessible.
When ghost is not at right time, hell is not
at chance for release.
When God is (not prayed) at right time,
whatever asking for does not come true.
古云： 天不得時，日月無光。地不得時，萬物不生。水不得時，風浪不靜。人不得時，利路不通。鬼不得時，地獄不超。神不得時，求之不靈。
We all know, if a right person can do the right things at right time at right place, with right people, this would lead to best efficiency for highest chance of successes. Here we talk about the magic word "RIGHT" , in fact has been since ancient time is one of the essential science of the Traditional Chinese Metaphysics (TCM), so as to target for a best start, best moment entering, best moment change, as well as for closure, etc.
《Tong Shu》says, "As per a general principle for auspicious day selection, having an auspicious year is not better than having an auspicious month setting; having an auspicious month is not better than having an auspicious day setting; having an auspicious day is not better than having an auspicious time (hour) setting. Because, year is like the root and stem of a plant, month is the branches and leaves, day would be the best strongest mature moment of the plant, time would be the fruits achieved from them."
《通書》云：
　　選日之宗旨，年吉不如月局，月吉不如日局，日吉不如時局。蓋年為根本，月為枝葉，日為華茂，時為結實。
What if in a predefined or prefixed given period, there is no suitable and best day for selection. Our ancient TCM masters had already envisaged such scenarios with some solutions but are considered as complex and senior knowledge-skill methodologys to accomplish with, one popular example is, QI MEN DUN JIA 奇門遁甲。
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