Chinese Geomancer's compass.

Geomancy is the art of successfully orienting buildings. The Chinese geomantic system is known as feng shui. In Chinese thought, feng shui is a system of good and evil influence in the natural surroundings, which needs to be taken into consideration when designing and siting buildings. Wooden compasses such as this one were used to determine the most healthy position to build a house. The location for buildings were carefully chosen so that the forces of Yin and Yang were balanced correctly, thus reducing the chance of illness.