With the knowledge of the current Earth Period we are currently in, based on the Earth Period Time System, we will be able to ascertain the birth, flourish, decline, and death (生旺衰死) of the Yin and Yang forms of the physical landforms on Earth. This is determined using both Luo Shu and the Early Heaven Eight Trigrams, to locate the Ling Shen (零神) and Zheng Shen (正神) directions.
Like the seasonal changes of nature, both the Yin and Yang forms of the physical landforms in Earth are subject to birth, flourish, decline, and death (生旺衰死), and this cycle can be ascertained from the Period Time System, or the Earth Period (地运) Time System to be precise, since it is pertaining to the Yin Yang forms in Earth.
The Eight Trigrams are represented by two arrangements, one being known as the Early Heaven Eight Trigrams (先天八卦), and the other being the Later Heaven Eight Trigrams (后天八卦). Early Heaven Eight Trigrams depicts an innate state whereby Yin and Yang are mutually opposing yet complementary and balanced.
In the Book of Changes (易经, Yi Jing), it says “是故，易有太极，是生两仪，两仪生四象，四象生八卦，八卦定吉凶”; Tai Ji (太极) gives rise to Liang Yi (两仪 ), Liang Yi give rises to Si Xiang (四象), Si Xiang gives rises to Eight Trigrams (八卦), and the understanding of auspiciousness through Eight Trigrams.
According to Chinese legend, during the pre-historic Emperor Yu’s (夏禹) time (Xia Dynasty), a “magical turtle” emerged from the Luo River, its shell marked with dots in a certain arrangement, now known as Luo Shu, the Luo River Inscription.
According to Chinese legend, it is said that Fu Xi (伏羲), one of the three sovereigns and five emperors in Chinese mythology, saw a mythological “dragon-horse” emerge from the Yellow River. It had black and white dots on its back, arranged in a specific pattern now known as He Tu (河图), the Yellow River Diagram.