Also known as bubble point, one of the four hole shapes of socket forceps mastoid. Refers to a hole with a slightly convex roof, where mountains and rivers are born and there are many plains. Liao Jun's Four Elephants Burial Method: "Suddenly, there is a slight bubble in the halo. Sudden, that is, the bubble is called sudden, so it is Lao Yang. Anyone who is dizzy, such as snails, shovels, breasts, blisters, is close at hand, and nothing will happen at a distance. " Guo Pu's "Buried Sutra" said that "it looks like a crown kettle and can be rich". Outbursts are divided into four categories, with large and small protrusions being positive lattices and double and triple protrusions being abnormal lattices. The emergent point must be sharp and smooth, and the emergent image should be implicit. If it is a sudden outbreak, it is for loneliness and burial. It is also necessary for dragons and tigers to guard the arch to gather the wind of the gas reservoir, and the mountain wind is taboo, and the water should be leveled. If the DPRK should be ruthless, the vertical point looks like a goldfish seal, which is also a fake flower. Sun Bogang's "National Treasure Classic" says: "If there is no dragon and tiger hug at the sudden point, it is not like the wind sweeping, or turning left and right, welcoming the water like a treasure."