First of all, there are hills in the south and plains in the north. The existence of these hills will naturally form some isolated areas between the houses of southerners. Their houses are generally scattered, so it doesn't matter whether there is a courtyard wall or not. In the north, people are used to living next to each other. In this case, it is difficult to define the area between them and their neighbors without the courtyard wall. In order to avoid disputes, a courtyard wall was set up.
Secondly, northerners are fascinated by the sense of ritual in building houses and have been working hard all their lives. If they can leave one or two houses for future generations, it will be a matter of pride for them. While building houses, they also pay great attention to design and geomantic omen, so the houses in the north are generally neat and are bungalows. Because the neighbors are relatively close, and they are all bungalows, if there is no courtyard wall, they will feel watched in broad daylight. In order to protect the privacy of family members, the existence of courtyard walls is also very necessary. Generally, houses in the south have their own designs, which will be designed into two or three floors according to their own preferences. The first floor is a warehouse, and the second and third floors are living rooms. Moreover, because they are not very close to each other, privacy issues will not be involved, so there is no need to set up fences.
Finally, some customs and habits also have a great influence on the housing design in the north and south. Before Beijing became the capital, the houses built were generally quadrangles, and Beijing was a relatively developed city in the north. Naturally, everyone tends to learn from Beijing. Siheyuan is a single-family courtyard with walls around it.