Luopan, it’s a tool used for investigating the geomantic omen, consists mainly of a celestial pool in the center of the disk and a series of concentric circles. Tianchi is composed of thimble, magnetic needle, submarine line, outer box and glass cover, fixed in the center of the inner disk. The seabed is the bottom of the Tianchi lake，there is a red line on it, named “submarine line”. This dish is made of wood, the color is yellow and has ten concentric circles outside the central Tianchi pool. Each circle represents the ancient Chinese people's understanding of a certain level of information in the whole system of everything in the world, such as the stars, myriad of things represented by the five ACTS, Chinese era etc all displayed on the compass.