Almost all the earth buildings have been tested by earthquakes to varying degrees and are safe and sound. Even if a good earth building experiences an earthquake, it just cracks a crack between buildings. Because the wall structure of the circular building is 1.2 meters thick below, it inclines slightly inward when extending upward, showing a ladder shape and strong centripetal force. For more than 70 years, it magically healed naturally, leaving only a crack one or two centimeters wide.
Another feature of the earth building is that the structure is extremely standardized, and the rooms are all the same size. Most earth buildings have only one gate for access, and they all have patios, which can store food for more than half a year. Just like a solid castle, it is easy to guard against theft and bandits (in the old days, Hakkas were often attacked by bandits, so tall earth walls were built to prevent accidents). Because the wall is tall and thick, it can not only prevent moisture and keep warm, but also insulate the heat and enjoy the cool, which has many benefits. When Hakka people build earth buildings, they build chimneys into the earth walls, so that the kitchen is clean without black smoke pollution.
The construction of tulou is also a manifestation of Hakka people's belief in geomantic omen in the old days. Superstition says that there is a "road evil spirit" on the road, a "stream evil spirit" on the stream and a "concave evil spirit" at the exit. When building a square building, they think that one corner of the building will encounter "Shaqi", so they carve the words "Taishan Shi Gandang" on the cornerstone of the corner of the building to ward off evil spirits, or nail the corner of the building with wooden boards with gossip and words to ward off evil spirits. Circular buildings have no edges and corners, and it is said that "Shaqi" can run away, so in order to avoid "Shaqi", earth buildings after the Qing Dynasty are mostly circular buildings. Generally speaking, it is obvious to emphasize the effectiveness of tulou.
Tulou is not only unique in architectural style, but also meaningful in naming most tulou. As a proud architectural form of Fujian Hakka, Tulou is a microcosm of the combination of "heaven, earth and people" and humanistic factors. There are dozens of families and hundreds of people living on the first floor, which embodies the family tradition of Hakkas living in groups and living in harmony. Therefore, a tulou history is a rural family history. Descendants of Tulou often can tell the origin of Kan Kan family without genealogy.
In addition, the use of local materials and the most common soil materials to build tall castles, turning ordinary into magic, reflecting the unique creation of Hakka people in the process of conquering nature. Since the 1960s, the construction of traditional earth buildings has basically stopped. Today, there are hundreds of earth buildings with different shapes in western Fujian and southern Fujian, among which Yongding County and Nanjing County have the largest number, each with more than 100 earth buildings. In Yongding, there are 54 earth building dens distributed in small towns such as Hukeng and Guzhu. In Nanjing, there are many towns such as Shuyang and Meilin. Most of the earth buildings are well preserved and still inhabited. It is mixed with ordinary houses, making the huge earth building stand out from the crowd.