Yingzao Fashi
The Song artist Zhang Zeduan's painting "Along the River During the Qingming Festival" depicts the Dongshui Gate in detail: the building on top had a five-ridged roof with a shallow slope in the Song dynasty style, supported prominently by two sets of brackets ("dougong"). The lower bracket assembly rested on the city gate to form a wooden foundation, while the upper assembly supported the roof, similar to the "dougong" in an extant Song building, the Goddess Temple in Taiyuan. This method of using bracket assemblies to support superstructure was specified in the 12th-century building manual "Yingzao Fashi" as "pingzuo" (literally "flat base").