Originating in the Tang Dynasty (618-907), Hakka tulou (earthen buildings) construction techniques are predominantly found in Nanjing county and Hua'an county in Fujian province. These techniques have been listed as a representative national intangible cultural heritage item under the category of traditional techniques.

Tulou typically features foundations made of cobblestones, strip stones, or large stones, elevated one to two meters above the ground. Thick rammed earth walls enclose the structure, supported by a through-tenon wooden structure that attaches to the walls, forming multi-story enclosed residential buildings.

The rammed earth walls provide external defense with their solidity, while the wooden structures divide space within the building. The overhanging eaves of tulou prevent rainwater from damaging the walls. They are commonly roofed with green tiles, often produced in specialized kilns to ensure quality. The materials used in tulou embody ancient wisdom and ecological consciousness.

The siting and construction of tulou adhere to traditional Chinese feng shui principles, emphasizing family prosperity and safety. The architectural design and layout prioritize scientific, rational, practical, and systematic considerations, reflecting modern living concepts.

Tulou is a globally unique masterpiece of residential mountain architecture, exemplifying the harmonious integration of village environments with natural landscapes. Tulou buildings in Nanjing county and Hua'an county are important branches of Fujian tulou, skillfully incorporating the feng shui principles of traditional Chinese architecture. Through the preservation of rammed earth technology, unique construction and comprehensive functionality, these tulous have allowed generations to live together harmoniously, enduring the tumultuous changes of time, making them vital parts of Chinese history.