Starting from Dinghu peaks, if we walk along the river up about 34 kilometers, and across the river, we will come to this gorge. The both sides of cliffs are dark, and the whole body of the cliff is like a castle constructed with irons. Go inside the gorge, the higher cliff, the more narrow valleys. The narrowest point allows only one person to pass through, so it is called Tiemen gorge. In the movie "Ashima," A Hei discharges an arrow from a bow here. Inside, it is very beautiful. It is surrounded by high cliffs and in the middle, there are full of green grass that is called Ganoderma dock. According to a legend that it is the place where the eight Immortals drank spring and had a taste of Ganoderma. Inside the dock there is a toft which is a site for four superiors to seclude in Ming Dynasty.