Why are there only 72 doornails on the Donghua Gate of the Forbidden City, while all other gates are 8 1?

The Forbidden City is the most outstanding representative of ancient China. It was the palace of 24 emperors in China during the Ming and Qing Dynasties. It has four doors, namely, the Wumen Gate, the Shenmen Gate, the Xihua Gate and the Donghuamen Gate, the most special of which is the Donghuamen Gate. People call Donghuamen' Ghost Gate' and' Yin Gate' because Donghuamen has the Meridian Gate, the Divine Gate and Xihua. Why are there only 72 nails in Donghuamen?

Palace doornails are generally 9 rows and 9 columns. The ancients always regarded 9 as the maximum number of yang, and the system of the son of heaven respected "9". There are only 72 doornails in Donghuamen, and there have been various speculations: it is said that they were confused with the doornails in Xuanwu Gate during construction; It is said that this gate is the "ghost gate" of the royal funeral, so even numbers are used to ward off evil spirits.

In fact, the doornail is not only the decorative component of the gate in the official building, but also its use level is strictly institutional; In the process of construction, these steps can not be completed independently by a certain type of work. Therefore, it is impossible to go wrong. According to the records in the archives of Ming and Qing Dynasties in the palace, all the quotations from Zigong, the funeral instrument of the Ming Empress, came from the Wumen Gate and passed through the Daming Gate. Only concubines, princes, and imperial daughters went out from Donghuamen to the south gate or the north gate of the East Gate, and the tombs in Xishan were peaceful. So in the next generation, Donghuamen has nothing to do with the emperor's life and death.

There is also a rumor that it has something to do with the geomantic omen that was followed when the Forbidden City was built. The buildings in the Forbidden City are all developed along the east-west axis, and the arrangement of doornails is related to geomantic omen. The position of Donghuamen needs to be set to 72, because the odd number 72 stands for "Yin", and the wooden door with 72 doornails stands at the position of Donghuamen, representing "Yin Mu". Wood can conquer the soil, which also changes the theory of haunted houses.

In fact, there are rules for the doornails of the prince's house: 63 princes in 7 rows and 9 columns, 49 princes in vertical and horizontal directions, and 25 princes in 5 rows and 5 columns. No matter how much, you should use iron nails. According to the law, ordinary people are not allowed to have doornails in their homes. Even if the owner has more money, he can't go beyond the system.