Masks like this would have been hung over house doors across China to frighten away evil spirits. The yin-yang symbol on its forehead is a common anti-demon device.Other door gods appear as a pair of fierce soldiers. According to legend a Chinese Emperor was kept awake at night by demons whistling and shouting outside his room. He ordered two men to keep guard outside his door and they did such a good job at scaring them off that he ordered a painter to paint their portraits and hang them outside his room. He slept soundly ever after.