In Tan dynasty, there is a famous fortuneteller enabled to do the prediction precisely on the street of the capitol city. One day, the king of Dragon, who was in charge of rain in the heaven, wanted to test how good the fortuneteller can predict. The king of Dragon disguised (transformed) himself  into an ordinary person and asked the fortuneteller that "When will it rain and how much?". The fortuneteller said "It will rain tomorrow noon for 3.3 inches." The king of Dragon was thinking, "I am the one in charge of the rain, not this fortuneteller. I will come to tear down his stand tomorrow."

Unfortunately, no sooner, the king of Dragon received the order from Jade Emperor, the emperor of gods, to rain tomorrow at noon for 3.3 inches." The king of Dragon was surprising and wasn't willing to follow this order. He postponed the raining schedule and extended the raining time. As a result, that rain caused the flood.

After the rain, the king of Dragon went to see the fortuneteller happily. But the fortuneteller said that "Don't you know you are in big trouble by disobeying the order of Jade Emperor?" The king of Dragon was completely shocked that the fortuneteller knew the true and ask for advise. The fortuneteller said general Wei of Tan dynasty  will come to see you to announce your death penalty, then he will kill you tomorrow at 45 minutes right after noon. The only chance is to ask help form the emperor of Tan dynasty. (In China, the dynasty emperor was the son of heaven).

That night, the king of Dragon entered the dream of the emperor of Tan, was on his knee to ask for help. The king of Dragon wanted the emperor of Tan to order general Wei staying in the palace tomorrow around 45 minutes after 12:00 PM.

On the next day, the emperor of Tan called general Wei in as his company in the early morning. They drank tea, visited the garden and played the chess. General Wei was kind of tired and had an nap during chess game. The emperor of Tan let him rest, because General Wei was still in his sight. After 45 minutes past noon, General Wei wake up, sweated and said about his bad dream. He said that, "The Jade Emperor called me up to the heaven. I saw a big shining golden dragon was tired up on a big column. The  Jade Emperor gave me a precious sword. He asked me to behead the king of Dragon and I did."

The emperor of Tan couldn't save the king of Dragon and very scare. He had the bad dream every night - the king of Dragon wanted the him to pay for his live. Someone suggested to let the most powerful and brave two generals, General Chin and General YuChih, standing by the bedroom door to guard the emperor all night long. Then there is no more bad dream for the emperor.

But they couldn't let General Chin and General YuChih to do the sentry job every night. So they find the painter to paint two general's portraits on the door. General Chin has pale face and General YuChih has dark face. General Chin wears tiger armor and holds a large ax and General YuChih wears lion armor and holds a metal-whip.

Therefore, people do the same way to paint the images of General Chin and General YuChih on their door as the god of door. They think the god of door can protect then from ghost or bad spirit to entering their house. Today, It's hard to find the image of god of door in the modern house. But we still can see the god of door in the temples.