The city of Beijing is formed by a succession of parallel alleys mainly crossing it from east to west, that have the ancient Mongolian name of Hutong. The width of these alleys varies from 3 to 9 meters. The Siheyuan courtyard houses form a continuous tissue, filling the space between the alleys; they are more or less 70m deep and about 20m wide. The main pavilions of each Siheyuan face south to make the most of the low winter sun. A row of pavilions placed to their rear protect the main buildings from the north-western winds.

An ancient architectural typology has been used to build the entire city of Beijing. Every single building is considered part of the whole, that is harmonized in a kind of great horizontal monument. Like the Hutongs, also the Siheyuans were built according to a project that has remained almost unchanged since the time of the Han Dynasty (206 B.C.-220 A.D.). The buildings forming each Siheyuan, organized in a sequence of courts, may house an extended family of up to three or more generations. The size and number of the courts originally depended on the social status of the owner. But regardless of the dimension, even a humble Siheyuan, that had low fences and doors rather than tall walls, featured the same plan as the residential district of the Son of Heaven in the Forbidden City. Other salient characteristics of the courtyard houses comprise the curved form of the roof, the visibility and refined design of the load-bearing wooden structure (beams, ledges, columns), the north-south axial arrangement of the buildings, the use of colour on the roof tiles and sometimes on the casing. Finally, an important characteristic consists on the regular proportions, both in the buildings and in the open spaces, and their implicit serenity, aimed at assuring the constructions are in harmony with the landscape and with Man. The wooden structure of beams and pillars that support the pavilions is the result of precepts that are older than the city itself. The proportion and definition of all wooden parts of a building were established in the Ying-tsao Fa-shi ("Building Standards") by Li Chieh, published in 1103 during the Dynasty of the Northern Sung. As a result, since the publication of this treatise all buildings are governed by a rigid system of standardization that has eventually become an essential element of Chinese architecture. The spaces of Siheyuan have proven very adaptable to changes during different periods of history. Since 1949, following the strategy of redistribution of dwellings, spaces that were originally occupied by one family were assigned to several nuclei. The wooden frame structure and the brick partitions, through simple rearrangements and constructions of new rooms, made it possible to adapt the buildings to a new lifestyle.