Jiugongge in Feng Shui
The fourth is the shoulder.
Eight or six is enough,
Left three right seven,
Nine plus one,
Five in the middle.
Xu Yue's Shu Shu Ji Yi in the Han Dynasty: "The number of nine palaces and the five elements are similar to each other." Zhen Luan of the Northern Zhou Dynasty wrote: "Nine palaces, that is, two or four are shoulders, six or eight are feet, three are left and seven are right, nine are worn, and five live in the middle." If you allow this, you can get the calculation diagram of Jiugong.
492
357
8 16
Four is southeast, nine is due south, and two is southwest.
Three are due east, five are in the middle and seven are due west.
Eight are northeast, one is due north and six are northwest.
Xu Yue said, "Jiugong calculation and five-element parameters are like a cycle", because the ancients endowed numbers with five elements and orientation attributes from one to nine. One, six is water, seven, two is fire, nine, four is gold, three, eight is wood, and five is earth. And it is a cycle of five elements, from water to fire → fire to gold → Jin Kemu → Mu Ke Tu → Tu Ke Shui. Orientation is: water in the north, water in the northwest, fire in the west, fire in the southwest, Jin Jiu in the south, gold in the southeast, wood in the east, wood in the northeast, and soil in the middle.
According to legend, after Fu won the world, he jumped out of the Yellow River on a dragon horse with a picture on his back, and the dragon horse dedicated this picture to Fu, so the river map is also called the Yellow River map. As for Luo Shu, it is said that when Dayu was in charge of water control, a turtle appeared from the water, carrying a book of nine numbers on his back, which he also dedicated to Dayu. It is said that this river map and Luo Shu both imply the truth of governing the country, so that these two sages can understand how to govern the country.
In the Song Dynasty, some people associated River Map, Luo Shu with the so-called "Nine Palaces". For example, Liu Mu mentioned in Yi Shu Diao Yin that the river map is the "Nine Palaces" and Luo Shu is a "map of several days" arranged by dozens. However, in the Zhu era, in the heyday of Neo-Confucianism, people turned the statements of He Tu and Luo Shu upside down, and thought that Luo Shu was a magic circle of numbers with one to nine rows of examples in vertical, horizontal and oblique directions, and the sum of numbers in all directions was fifteen, while He Tu was a series of numbers added from one to five, which was also said by later generations to be the origin of the mystery of China's mathematical magic circle. In divination, astrology or geomantic omen, the river map and Luo Shu often become the source of his theory, which can be said to be the root of China's "five skills" (mountain, medicine, life, physiognomy and divination).