Ancient Chinese architecture has numerous similar elements in part, because of the early Chinese method of standardizing and prescribing uniform features of structures. The standards are recorded in bureaucratic manuals and drawings that were passed down through generations and dynasties. These account for the similar architectural features persisting over thousands of years, starting with the earliest evidence of Chinese imperial urbanism, now available through excavations starting in the early 1980s.
A fundamental achievement of Chinese wooden architecture is the load-bearing timber frame, a network of interlocking wooden supports forming the skeleton of the building. This is considered China's major contribution to worldwide architectural technology. However, it is not known how the builders got the huge wooden support columns into position.
Unlike western architecture, in ancient Chinese wooden architecture, the wall only defined an enclosure, and did not form a load-bearing element. Buildings in China have been supported by wooden frames for as long as seven millennia. The emergence of the characteristic articulated wooden Chinese frame emerged going back to the Neolithic Age. As long ago as seven thousand years mortise and tendon joinery was used to build wood-framed houses, and persists in Lijiang's old city today.