Defense qì

A qì described as being fierce, bold, and uninhibited, unable to be contained by the vessels and therefore flowing outside them. In the chest and abdomen it warms the organs, whereas in the exterior it flows through the skin and flesh, regulates the opening and closing of the interstices (i.e., the sweat glands ducts), and keeps the skin lustrous and healthy, thereby protecting the fleshy exterior and preventing the invasion of external evils. The Magic Pivot (灵枢 líng shū, běn zàng piān) states, defense qì warms the flesh and flushes the skin; it keeps the interstices replenished and controls their opening and closing. If defense qì is in harmony, the skin is supple and the interstices are kept tight and sound. Since defense qì has a warming power, it is sometimes referred to as defense yáng.