Buddhism takes the "emptiness" of various laws as the way to enter the Tao, so it is called "emptiness". Everything comes from karma, there is no fixed self, and it is illusory and unreal. This is the so-called "emptiness". As stated in Volume 20 of Great Wisdom, there are three gates to enter the city of Nirvana: an empty gate, a non-phase gate and a reactive gate. There are many contents of "empty door", such as I am empty, I am empty, I am empty, I am empty, and I am empty. The sutra of the great monarch says "sixteen empty spaces" and great wisdom says "eighteen empty spaces". Tiantai Sect lists "empty door" as one of the "four laws", that is, there are doors, empty doors, empty doors and non-empty doors. In Buddhism, the essence of "emptiness" and the phenomenon of "being" are unified. "Empty Gate" plays an important role in Buddhism, because it refers to Buddhism. For example, Wei's poem "Sighing White Hair" says, "How many sad things have you had in your life? Don't sell them to an empty net." Also refers to the Buddhist temple. For example, Yu Dafu's The Journey to the West and Journey to the West Tianmu: "We are all a little unhappy and forget to come back. We should learn from the father of Zhao Ming, the oldest prince in the legend of Tianmu Mountain, and prepare to give up our bodies. " Liang Wudi, the father of Prince Zhaoming, became a monk in Tongtai Temple three times. Buddhist temples are called "empty doors", and so are monks in Buddhist temples. For example, in the volume "Stone Shi Yao Fairy", it is said: "Monks enter Nirvana House and pass through this gate (empty gate), hence the name" empty gate ". The "empty door" in the poem also refers to the deserted door. Such as Tang Hantao's poem "Ge Yanxing": "The male sword holds the dust box, and the empty door is only a sparrow."