stylistic:tone, structural:reformatting, information:extraction
Historical Chinese construction

Under the prescription of the Method of Construction (營造法式) issued by the Song dynasty government in the early twelfth century, timbers were standardized to eight cross-sectional dimensions. Regardless of the actual dimensions of the timber, the ratio between width and height was maintained at 1:1.5. Units are in Song dynasty inches (31.2 mm).

Timber smaller than the 8th class were called "unclassed" (等外). The width of a timber is referred to as one "timber" (材), and the dimensions of other structural components were quoted in multiples of "timber"; thus, as the width of the actual timber varied, the dimensions of other components were easily calculated, without resorting to specific figures for each scale. The dimensions of timbers in similar applications show a gradual diminution from the Sui dynasty (580–618) to the modern era; a 1st class timber during the Sui was reconstructed as 15×10 (Sui dynasty inches, or 29.4 mm).