英文說明:This ruler is marked with two measurement scales. One edge is markedwith a wengong scale while the other has a dinglan scale.The top edge has a total of ten units, with each bearing a name (ding, hai, wang, ku, mei, gong, si, xing, shi, cai) with either an auspicious or unlucky meaning. When the carpenter began work, it was essential to use a "lucky" measurement. The height, length and width of the project had to avoid unlucky spans, such as "ku" [bitterness], "si" [death] or "shi" [loss]. Optimally, the measurements should use units like ding [able-bodied man], guan [government official], xing [to be happy] or cai [wealth]. The ruler displayed here is complete.