The construction ruler (营造尺,Yingzao chi) for this hall is 320.6 mm. It adopts the system of large and small rulers that has been in practice since the Tang and Song dynasties. Each large ruler is divided into 10 cun(寸), which is equivalent to 12 small cun(小寸). It uses architectural modulus similar to modern ones. The basic module is 1 chi. Based on this, the macroscopic dimensions are determined and the proportion of the main body is controlled. Four small cun are used as the sub-module, which is one-third of the basic module. Half a chi, that is, six small cun, is also a sub-module of one chi. Based on this, the height of columns, the height of bracket sets, etc. are determined. 0.4 small cun are also a sub-module, which is one-thirtieth of the basic module. This is used to measure various components, such as dou (斗,square blocks), gong (栱,cross-shaped brackets), and fang (枋,horizontal bars).