Tulou means "earth building". It is named from its outer walls, which are made from rammed earth. Generally speaking, the large multi-storey Tulou was seldom seen in the areas where early Hakka lived. However, they are appeared in the perimeters of Hakka and other ethnic groups or around locations where Hakka fast developed after Ming and Qing dynasties.
The Tulou in the Fujian Province is divided into three types, Wufeng, Rectangular, and Round. Wufeng are located mainly in Yongding, and rectangular and round Tulou are distributed in Nanjing , Pinghe, Zhaoan West and Yongding East. In most of the villages, round and rectangular tulous are mixed together. Among three kinds of Tulous, the rectangular Tulous were the original ones.
The Wufeng tulous are obviously the results of a redesign of the Chinese courtyard by the Hakkas. "Three halls and two side rooms" are a feature of the Wufeng tulou. The side rooms are the heightened wing-room of the Chinese courtyard. The center hall in the back yard becomes a multi-storey building. The earth walls in the four sides are enclosure. This was not only for defense reasons, but also as an expression of traditional Chinese architectural forms.
In reality, the rectangular Tulous were built earlier than round ones. For example, in the northern part of the Guzhu, Yongding, the rectangular tulou, named Wuyun Tulou was built five or six hundred years ago, while the round shape, Chengqi had only been built for three or four hundred years.
The round Tulou has distinct characteristics. It is high, giant, and complex. Generally speaking, round Tulous can be divided into small, medium, and large types. Small round tulous are normally two or three storeys and consist of a single ring; medium round tulous are three or four storeys high and have wide diameters or two rings; large ones are four or five storeys with two rings or even three rings. A large number of round tulous are of medium size. The Tulou is occupied normally by a kin group. As a result it is more like an apartment or a small village rather than a single building.
Round Tulous normally have only one fortified door. Behind the door is the foyer. This is not only the major access, but also the public space for the occupants. The natural ventilation is ideal. No matter what size and how many storeys of round Tulous, the room sizes are the same at the same location on each floor. The ground floor is always the kitchen.
If there are only two storeys, the first floor becomes the bed-room. Most round Tulous are three or four storeys. The first floor becomes a storage room for food and furniture. The storage room does not have any windows. The second floor and above are bedrooms in this case. They have small windows, which open to the outside, and a larger widow opening to corridor. The corridors are built on the extension of the beams of the lower floor. As a result, the ground floor is free of columns, and creates a large open space. The interesting thing is the small eaves on the second or third floors. The obvious function is for drainage. However, the space created under the eaves can be used as a storage place.