Refers to the place and method of breathing when singing and chanting. Regarding ventilation, Yuanyan Nanzhi'an's "Singing Theory": "There are stealing breath, taking breath, exchanging breath, resting breath, taking breath, and there is a breath of love." According to the different needs of music melody, rhythm and emotion, there are different ways to handle the breath: some need to be completed in one breath without leaving a breath, and the flow is like a pearl, and the momentum wins; some are slower and have intermittent moments, and a large mouth can be used to be calm and unhurried , is good at slowness; some use small breaths for quick breaths when the speed is fast or complicated, and the words are quick and fast, and the tendons are stimulated; some even use the method of stealing breath when the flow is continuous. Make up for the lack of breath. In addition, the methods of breaking, connecting, stopping, and frustrating are also closely related to the use of Qi and the treatment of the air mouth. The arrangement of the breath mouth and the application of ventilation techniques not only involve various methods of handling the accent, but also play an important role in expression in opera singing (playing).