Zhenchenglou, Communal fortress residence in Hongkeng village, China.

Zhenchenglou is a circular fortress residence in Hongkeng with a double ring structure consisting of 184 rooms across four stories on the outside and 32 rooms on two levels inside. The rammed earth walls are reinforced with bamboo, creating a strong construction that has endured for over a century.

Zhenchenglou was built in 1912 by Lin Hongchao and his brothers, of the 21st generation of the Lin family of Hongkeng. It was listed as a Yongding County cultural relic in 1988, a Fujian provincial cultural relic in 1991, and a national key cultural relic in 2001. In 2008 it became one of the 46 Fujian Tulou inscribed on the World Cultural Heritage List.

The building reflects traditional Hakka community life, where multiple families lived together while keeping their private spaces separate. Visitors can see the shared courtyards that brought residents together for daily activities and gatherings.

The structure is well-preserved and navigable, with staircases and pathways connecting the inner areas. It helps to arrive early in the day when fewer visitors are present and light reaches the indoor spaces more clearly.

The building's layout follows the eight trigrams of Bagua, a principle from Chinese philosophy that divides the outer ring into four distinct areas. Each section served different family and craft functions, creating a purposeful design.