The Heaven Plate, the Earth Plate, and the Monthly General

The theoretical system of Liu Ren (六壬) is essentially a geocentric spatiotemporal model centered on the Earth. The Earth Plate (地盘) can be understood as the terrestrial realm, where the twelve branches of the Earth Plate represent twelve fixed directions. The Monthly General (月将) can be understood as the Sun, which moves with time and cycles through the twelve palaces of the zodiac.

The Earth Plate: In the Da Liu Ren (大六壬) system, the Earth Plate is usually placed at the very bottom. It is fixed and cannot rotate, generally representing units of time and spatial directions. For convenience in writing, Liu Ren chart formats often write only the Heaven Plate (天盘) and omit the twelve branches of the Earth Plate. In practice, however, the Earth Plate does not disappear; it remains permanently fixed beneath the Heaven Plate.

The Heaven Plate: The Heaven Plate is dynamic. Arranging it is the first step to cast a chart in Da Liu Ren. Its core rule places the Monthly General over the divination hour, rotating clockwise to generate the Heaven Plate. For example, after identifying the Monthly General, place it over the hour on the Earth Plate. Assuming the Monthly General is the Tiger general and the divination hour is the Pig (Hai 亥) hour, place Tiger (Yin 寅) on the Heaven Plate over Pig on the Earth Plate. Then rotate clockwise in sequence to distribute the Heaven Plate. Rabbit (Mao 卯) on the Heaven Plate appears over Rat (Zi 子) on the Earth Plate, Dragon (Chen 辰) on the Heaven Plate appears over Ox (Chou 丑) on the Earth Plate, Snake (Si 巳) on the Heaven Plate appears over Tiger on the Earth Plate, and so on. The Heaven Plate is dynamic, changing with the double-hours and completing one full rotation each day.

The Monthly General: The Monthly General, also called the Sun (太阳), refers to the general on duty as the sun passes through the zodiacal palaces. The sun passing through palaces means the sun moves through the twelve zodiacal palaces. The ancients used the twelve Monthly Generals to represent the positions of the sun in different zodiacal palaces. In Liu Ren, the Monthly General is essentially a symbolic representation of the sun. The ancients called the path of the sun revolving around the Earth the ecliptic. They divided the ecliptic into twelve sectors, known as the twelve zodiacal palaces, which are respectively represented by the twelve Monthly Generals. Therefore, the position of the sun within the twelve zodiacal palaces is indicated by the Monthly General in Liu Ren. Note that the Month Branch (月建) and the Monthly General are two different concepts and must not be confused. The Month Branch refers to the Earthly Branch (地支) corresponding to each lunar month. It represents the seasonal qi of the Month Branch, used to evaluate the Five Elements (五行) being Prosperous (旺), Supported (相), Resting (休), or Confined (囚). In contrast, the Monthly General is the general on duty formed by the movement of the sun through the twelve zodiacal palaces, representing the symbol of the sun itself. The Month Branch emphasizes solar terms and elemental climates, while the Monthly General emphasizes the sun's passage through the palaces and how to cast a chart. The Month Branch determines whether the Five Elements are Prosperous, Supported, Resting, or Confined, whereas the Monthly General itself is not evaluated in terms of being Prosperous, Supported, Resting, or Confined. A fixed relationship exists between the Month Branch and the Monthly General: after a Major Solar Term, the Month Branch and the Monthly General form a Combination (六合). For example, the first month establishes Tiger, and after Rain Water, the Pig general is used, forming a Tiger-Pig Combination. The second month establishes Rabbit, and after Spring Equinox, the Dog (Xu 戌) general is used, forming a Rabbit-Dog Combination. Therefore, remembering the Month Branch allows one to deduce the Monthly General. After a Major Solar Term, the Earthly Branch in Combination with the Month Branch becomes the Monthly General. Before a Major Solar Term, one uses the next Earthly Branch following the one in Combination with the Month Branch as the Monthly General.

The rules for employing the Monthly General are as follows: After Rain Water in the first month, the sun moves into the Pig palace, and the Pig general is employed. After the Spring Equinox in the second month, the sun moves into the Dog palace, and the Dog general is employed. After Grain Rain in the third month, the sun moves into the Rooster (You 酉) palace, and the Rooster general is employed. After Grain Buds in the fourth month, the sun moves into the Monkey (Shen 申) palace, and the Monkey general is employed. After the Summer Solstice in the fifth month, the sun moves into the Goat (Wei 未) palace, and the Goat general is employed. After Major Heat in the sixth month, the sun moves into the Horse (Wu 午) palace, and the Horse general is employed. After the End of Heat in the seventh month, the sun moves into the Snake palace, and the Snake general is employed. After the Autumnal Equinox in the eighth month, the sun moves into the Dragon palace, and the Dragon general is employed. After Frost's Descent in the ninth month, the sun moves into the Rabbit palace, and the Rabbit general is employed. After Minor Snow in the tenth month, the sun moves into the Tiger palace, and the Tiger general is employed. After the Winter Solstice in the eleventh month, the sun moves into the Ox palace, and the Ox general is employed. After Major Cold in the twelfth month, the sun moves into the Rat palace, and the Rat general is employed.

The evolution of the Heaven Plate refers to placing the Monthly General over the divination hour on the Earth Plate and arranging the twelve branches in clockwise order. The resulting plate configuration is the Heaven Plate. When studying Liu Ren, one must firmly memorize the positions of the twelve branches on the Earth Plate. The Earth Plate remains forever fixed: Rat (Zi 子) is in the true north, Horse (Wu 午) is in the true south, Rabbit (Mao 卯) is in the true east, and Rooster (You 酉) is in the true west, with the remaining Earthly Branches arranged in sequence. To cast a chart, one only needs to determine the Monthly General, place it over the divination hour, and arrange the twelve branches in clockwise order to set up the Heaven Plate.

Regarding the Monthly General and the Heaven and Earth Plates (天地盘), one must keep the following points in mind: First, the Earth Plate represents the divination hour and directions, remaining forever fixed and unmoving. The twelve branches of the Earth Plate are both the twelve double-hours and the twelve directions, serving as the foundation of the Liu Ren space-time model. Second, the Earth Plate comes before the Heaven Plate. The Heaven Plate is formed by placing the Monthly General over the divination hour; without the fixed Earth Plate, the Heaven Plate cannot be established. Although the Earth Plate is often omitted in writing the chart format, it always lies beneath the Heaven Plate. Third, the Earth Plate governs stillness, while the Heaven Plate governs motion. The Earth Plate represents fixed directions and the substance of the earth; the Heaven Plate is formed by rotating the Monthly General, representing the dynamic qi of the sun's motion. The Earth Plate is like the sustaining earth, and the Heaven Plate is like the revolving heaven. Through stillness and motion, heaven and earth intersect, and the imagery of the Liu Ren chart takes shape. Therefore, the Monthly General is an extremely critical concept when casting a chart in Liu Ren. It is not only the basis for setting up the Heaven Plate, but also represents the palace on which the sun arrives during that month. Only by understanding the Monthly General can one understand how the Heaven Plate is generated. Only by understanding the Heaven Plate can one further comprehend how the Four Lessons (四课) and the Three Transmissions (三传) are derived from the Heaven and Earth Plates. Students of Liu Ren must build a solid foundation here and never neglect it.