### Earth Period Time System

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. In this Earth Period Time System, time is made up of eight Periods as mentioned before, each governing a specific number of years and this is determined from both Luo Shu and Early Heaven Eight Trigrams.

Cross referencing both Luo Shu and Early Heaven Eight Trigrams, one can observe that Kun Trigram (坤卦) is in charge of Earth Period 1, Xun Trigram (巽卦) is in charge of Earth Period 2, Li Trigram (离卦) is in charge of Earth Period 3, Dui Trigram (兑卦) is in charge of Earth Period 4, Gen Trigram (艮卦) is in charge of Earth Period 6, Kan Trigram (坎卦) is in charge of Earth Period 7, Zhen Trigram (震卦) is in charge of Earth Period 8 and Qian Trigram (乾卦) is in charge of Earth Period 9. As there is no Trigram in the centre, there is no Earth Period 5.

From this, we can further observe that the four Yin Trigrams of Kun, Xun, Li and Dui is in charge of the Earth Period 1, 2, 3 and 4 respectively, together known as the Upper Yuan , whereas the four Yang Trigrams of Gen, Kan, Zhen and Qian is in charge of the Earth Period 6, 7, 8 and 9 respectively, together known as the Lower Yuan . Hence, the Earth Period time system is also known as Two Yuan Eight Period (二元八运) Time System.

As for the number of years each Period governs, it is derived based on the Yao (爻) of each Trigram and based on the principle of Yang 9 years Yin 6 years (阳九阴六).

**Earth Period 1:**

Kun Trigram is in charge of Earth Period 1, and based on the principle of Yang 9 Yin 6, Kun Trigram (☷) with 3 Yin Yao hence 3 x 6 = 18, thus the total number of years in Earth Period 1 is 18 years, starting from the first pairing of Heaven Stem-Earth Branch in the sexagenary cycle; from Jia-Zi (甲子) Year to Xin-Si (辛巳) Year, recent years being starting from the Year 1864 to Year 1881 .

**Earth Period 2:**

Xun Trigram is in charge of Earth Period 2, and based on the principle of Yang 9 Yin 6, Xun Trigram (☴) with 2 Yang Yao and 1 Yin Yao hence 2 x 9 + 6 = 24, thus the total number of years in Earth Period 2 is 24 years, from Ren-Wu (壬午) Year to Yi-Si (乙巳) Year, recent years being starting from the Year 1882 to Year 1905.

**Earth Period 3:**

Li Trigram is in charge of Earth Period 3, and based on the principle of Yang 9 Yin 6, Li Trigram (☲) with 2 Yang Yao and 1 Yin Yao hence 2 x 9 + 6 = 24, thus the total number of years in Earth Period 3 is 24 years, from Bing-Wu (丙午) Year to Ji-Si (己巳) Year, recent years being starting from the Year 1906 to Year 1929.

**Earth Period 4:**

Dui Trigram is in charge of Earth Period 4, and based on the principle of Yang 9 Yin 6, Dui Trigram (☱) with 2 Yang Yao and 1 Yin Yao hence 2 x 9 + 6 = 24, thus the total number of years in Earth Period 4 is 24 years, from Geng-Wu (庚午) Year to Gui Si (癸巳) Year, recent years being starting from the Year 1930 to Year 1953.

**Earth Period 6:**

Gen Trigram is in charge of Earth Period 6, and based on the principle of Yang 9 Yin 6, Gen Trigram (☶) with 2 Yin Yao and 1 Yang Yao hence 2 x 6 + 9 = 21, thus the total number of years in Earth Period 6 is 21 years, from Jia-Wu (甲午) Year to Jia-Yin (甲寅) Year, recent years being starting from the Year 1954 to Year 1974.

**Earth Period 7:**

Kan Trigram is in charge of Earth Period 7, and based on the principle of Yang 9 Yin 6, Kan Trigram ((☵) with 2 Yin Yao and 1 Yang Yao hence 2 x 6 + 9 = 21, thus the total number of years in Earth Period 7 is 21 years, from Yi-Mao (乙卯) Year to Yi-Hai (乙亥) Year, recent years being starting from the Year 1975 to Year 1995.

**Earth Period 8:**

Zhen Trigram is in charge of Earth Period 8, and based on the principle of Yang 9 Yin 6, Zhen Trigram (☳) with 2 Yin Yao and 1 Yang Yao hence 2 x 6 + 9 = 21, thus the total number of years in Earth Period 8 is 21 years, from Bing-Zi (丙子) Year to Bing-Shen (丙申) Year, recent years being starting from the Year 1996 to Year 2016.

**Earth Period 9:**

Qian Trigram is in charge of Earth Period 9, and based on the principle of Yang 9 Yin 6, Qian Trigram (☰) with 3 Yang Yao hence 3 x 9 = 27, thus the total number of years in Earth Period 9 is 27 years, from Ding-You (丁酉) Year to Gui-Hai (癸亥) Year, recent years being starting from the Year 2017 to Year 2043.

**Overview of Recent Years Period:**

Period 1 – Year 1864 to Year 1881

Period 2 – Year 1882 to Year 1905

Period 3 – Year 1906 to Year 1929

Period 4 – Year 1930 to Year 1953

Period 6 – Year 1954 to Year 1974

Period 7 – Year 1975 to Year 1995

Period 8 – Year 1996 to Year 2016

Period 9 – Year 2017 to Year 2043

From the above information, we are now able to tell in which Earth Period we are currently in. Based on the above information, we are at the beginning of Earth Period 9, which starts from Year 2017. Hence one can say that we, or rather all houses, are currently in Earth Period 9. Knowledge of the Earth Period Time System is an important factor in the Fengshui assessment of properties and landforms and one that must not be overlooked.