Liu Zi Jue or Six Healing Sounds:
This form of Qigong has an origin from 420 to 589 AD when Tao determined that there are six different ways/sounds to exhale, which forms different vibrations that affect different organs. These vibrations assist in rectifying/balancing the function of these organs.
The sounds were prescribed to be used to treat various ailments such as lung and heart disease. Later (1368 to 1644 AD) it was documented that combining these sounds with gentle graceful movements then improves the health of the different organs and related issues:
XU for liver, HE for heart, SI for lungs, HU for spleen, CHUI for kidneys, and XI for regulating heat in Sanjiao (the term for the three bodily zones: Upper chest, thorax, and abdomen).