Mujiang square
The full name is "Luban Building Ruler", also known as "Lu Banchi", which is a measuring tool used in building houses, similar to the bending ruler used by craftsmen today. Lu half a foot is about 46.08 cm long. It is said that it was written by Lu Ban, the Duke of Lu in the Spring and Autumn Period. Later, it was added to the geomantic circle to measure the good and bad luck of houses and houses, which was called "door plan".
Also known as "square", it is mainly used to check whether the planed plates, purlins and structures are vertical and whether the edges are at right angles to each other. 1 city ruler =0.8 half a foot. Soon after, Lubanchi appeared, Ding Lan ruler was integrated, and then inches and centimeters were integrated. It is an important tool for measurement and calibration. Because of its special function, it is most widely displayed in geomantic culture and architectural culture.