Also known as five households, earth axis, lying hand, sweeping down, shaking down, and Shimonoseki, it refers to the outlet of water flow in Dongtian. Xu Shanji's "Instructions of the Son of Man: Sofa" says: "There are also five households, and they want to keep it secret. Cover the hole or so, don't ask the dragon and white tiger. When the water goes, it's called Lu Hu. It should be high and close, and the water will be diverted to Ji Fang. " Feng Shui experts believe that the close relationship between landlords and tenants is a sign of the real dragon node. Miao Xiyong's "Twenty-four Difficult Questions" said: "The dragon in Zhi Zhi has no sand, and the dragon can't do without sand." Huang Chao should have said in "Bo Shan Pian On Water": "Look for the Longmen, acupuncture, closing the mouth and looking at the sand. If the dragon is alive, the nozzle is narrow, and if the dragon is not alive, the nozzle is wide. " Water vapor is an external form of anger. It's a heavily guarded place with flashy watches at the door, full of gas, swords and halberds hanging high, surrounded by horses, chariots and lions, geese and couples. They don't vent their anger, it is a big and expensive place. If Shimonoseki is empty, there is no need to find a hole. Water vapor is also a symbol of wealth. If the land is careful, there will be no leakage of wealth. "Shuikou" says: "Where the water goes, it is called a land household. If there is no water, it is called a land household closed. The husband's water is the main wealth, and when the door is open, the wealth comes, and when the door is closed, the wealth is inexhaustible. " If it doesn't matter at all, the water will be straight, which is a sign that wealth will be scattered and people will die. Preface to Encyclopedia of Geography and Encyclopedia of Mountain Law: "If you go to the mouth, you will be closed tightly. You are most afraid of going straight and getting nothing."