Originally, there were archways (archways), Dongdan archway, Xidan archway and Xisidong archway, which were all demolished later.
It was called Dashi Street when it was four yuan east and four yuan west, and it was very lively. It was a prosperous business district in the Yuan Dynasty. After the establishment of Yuan Duyi, it was called the "Old Privy Council Corner City" and belonged to Mingzhaofang. At that time, "Privy Council City in Cape" had many businesses and shops, and it was one of the three major commercial centers in the city. There is a towering archway with three rooms, four columns and three floors in the east, west, north and south of Dongsi intersection, which are called Sicheng Square, Renshou Square, Baodafang and Zhao Ming Square respectively. The four archways at Xisi intersection face the letters "Great World" from north to south. The archway in the east is called "Ren Hang" and the archway in the west is called "Coco". Later, these four archways had new names: Jincheng Square, Mingyu Square, Qing Ji Square and Anfu Square.
Because there are four independent archways in Dongsi and Xisi, people no longer call them "streets", but simply call them Dongsi and Xisi archways. It will be more convenient to call it "four arches" in the future. When Beiping was liberated, these archways were still alive. It was demolished in the 1950s to expand the road. Without the archway, it is easier to call it "Dongsi" and "Xisi".
This is how Dongdan and Xidan came. The word "single" is because the archway here is single collapsed. The archway in Xidan is called "Zhan Yun" and the archway in Dongdan is called "Nine Days". In this way, Dongdan archway and Xidan archway were opened. Similarly, in 1950s, when roads were expanded and archways were demolished, there were only "Dongdan" and "Xidan".
2. The source of the name "Dashilan"
The name of Dashilan began to spread during the reign of Kangxi. At that time, Kangxi lived in the Forbidden City and ordinary people lived outside the city. In order to do a good job in public security, Emperor Kang issued an order stipulating that the hutongs outside the city should also be fenced at the hutong mouth. Because the front door is close to the Forbidden City and the fence is higher than other places, it is called "Dashilan".
Dashilaner is a dialect in Beijing, but this name has been called for hundreds of years and has formed a specific noun and concept. This is different from the dialect in ordinary everyday language. There is a place in Beijing called Dashilan, which is just an alley in Xichang Street and another place.
Professor Zhou Yimin, who studies modern Chinese in the Chinese Department of Beijing Normal University, believes that the pronunciation of Dashilan belongs to the special pronunciation of place names, and the long-standing pronunciation of Dashilan belongs to the preservation of ancient sounds. Although there is no special standard for place names in China at present, it is specifically mentioned in the broadcasting textbooks that "Dashilan" should be pronounced.