What do the names Dongdan and Xidan in Beijing mean?

Dongdan and Xidan are place names that Beijingers have long been familiar with. When people pass by in a hurry, few people will explore the reasons for their naming, but many people will think these two place names are very special. Beijing is a masterpiece of the ancients, and its bricks, tiles, grass and trees all have meanings, so there must be rich cultural genes behind these two place names. Where did its name come from?

According to the textual research of Lu Sixian's mythology and archaeology, the word first appeared in Oracle Bone Inscriptions, which is an pictographic character shaped like a horn. There are four steps around Yin, the capital of Shang Dynasty: Dongdan, Xidan, Beidan and Nandan. Hu Houxuan interpreted "Dan" as a flat land in the countryside, and he interpreted "Dan" as a platform, a platform made of soil, and Ding Shan as an altar. "Dan" is to build an altar, that is, a high platform, on a flat open space as a place for sacrifice and dancing. Zhu said Nandantai was another name for Lutai, while Guoyu said that Taiwan Province was looking forward to disaster, which explained the nature and use of "Dan" as "Taiwan". "Lutai" is marked by deer, so it is necessary to set up a deer head column, which is the characteristic of Nandantai. The "looking at the atmosphere" here, that is, observing the sky and weather, is equivalent to the Lingtai of the Zhou Dynasty. Therefore, Oracle Bone Inscriptions said "Nandan", which is the "single" in the myth of building wood, and described the position of the meridian on the sun, indicating that the "single" in Shang Dynasty was the proper name of the shadow measuring rod. Busch also said: "Xidan thunder" clearly observed the weather here. This is the main purpose of "Dan". Of course, festivals and dance activities are also held here.

Therefore, in ancient Chinese characters, the horizontal bar was a tool for measuring the shadow of the sun in ancient times, which was later the sundial. The sundial is the shadow of the sun, and the earliest method to measure the shadow of the sun is the "immediate effect". "Zhou Li Kao Gong Ji" is about putting a wooden pole vertically on the horizontal ground with a rope, then making a circle with the wooden pole as the center, and observing the sun's shadow cast on the flat ground. The positive east-west direction, that is, "seize the day", can be obtained by connecting two points where the shadows of sunrise and sunset intersect with the circumference. The ancients erected poles on the empty flat ground, with the purpose of observing the shadow of the sun, measuring time, orientation and setting solar terms.

The so-called Dongdan means sunrise in the east. In ancient times, the East symbolized spring, that is, the position of the sun at the vernal equinox was determined with "Dan" as the vertical pole. Lu Sixian said that in bronze inscriptions, "Xidan" is a combined word, and "Xi" is shaped like a bird's nest, meaning that the bird's nest is built on a tree. Or add a bird word and a word in the middle, indicating that the bird returns to its nest in the west, which means sunset scene. Add the word "eye" to one side of the word, which means observing the sky at sunset. Here, it means measuring the autumnal equinox.

Dongdan and Xidan in Beijing are the names of Dongdan and Xidan, which originated from the capital of Yin and are the names left over from ancient times. But why is the intersection called Dongdan Xidan?

According to Bao's Notes on Ancient and Modern Times, Chinese watches, also known as table wood, are used to erect poles and measure shadows. It stands at the crossroads: "Passing the crossroads (that is, the crossroads) is called Shi Yan, or Biaomu ... Now Xijing is called cross-afternoon wood." The so-called "crossing noon" means that the shadow of the sun at noon is due north and south. After this moment, the sun moved to the west and the shadow turned to the east of the column. The ancients called it "anti-scene" or "Xidan scene", indicating that the ancient people used a pillar to measure the shadow, and the light of the sun was called "Hua", so this pole was called "Hua Biao". There is a word "line table" in the bronze inscription, that is, a four-corner diamond symbol is drawn above the word to indicate the direction of the four corners; The two sides of the word "single" are combined into a "row", indicating that there is a "single" in the center of the cross street, indicating four positive directions; Together, use a "single" to measure the four corners of the square.