There are quite a few breathing methods in qigong. Zhongxi or taixi, as mentioned in Xing Ming Gui Zhi Qian Shu (A Comprehensive Collection of Methods on the Training of Shen and Regulation of Jing and Qi) published in the Qing Dynasty, refers to such a breath that goes all the way to the mingmen point through the midline of back and links with the prenatal qi as a result of mutual attraction. The second method is fushi huxi. That means that you expand your lower abdomen whilst in-haling but contract it whilst exhaling. You can also do it quite abnormally, contracting your lower abdomen when you inhale but expanding it when you exhale. The third one is pifu huxi (breathing through the skin) which requires you to feel all the pores of your body are open to the outside so that you can exchange qi for air. The fourth is guixi. When you breathe in this way, you are doing it like a tortoise. The fifth is shuxi (counting breath), and when you do it, try to count your breath in a quiet way. The last but not the least is tingxi (listening to breath), during which time you can sense your breath in a quiet way.

In a word, the regulation of breath should be gentle and light and without any :noise or obstruction, and when you have a vague idea of your breath, you will have achieved the harmony of shen and qi.