I have wrestled with understanding shao yin. My struggle with understanding shao yin and in simple terms just become clear. Let me share.
All things can be defined by the theoretical knife of yin and yang. Shao yin contains two parts, a yang and a yin part.
Shao yin contains two of the five elements which are opposite of each other and namely Fire and Water.
Shao yin is connected to the tai yang which also contains the same two elements.
Tai yang and shao yin both represent the Fire and Water element and they balance each other. Fire must make its descent into Water to create qi as vapor and Water must rise to cool Fire.
In tai yang cold rules and in shao yin heat rules.
If tai yang is a yang energy how can cold rule? And if shao yin is a yin energy how can heat rule?
Tai yang needs to contain more yang energy so normal function on the outermost parts of the kingdom can function. This yang energy comes from the shao yin and tai yin. Tai yang is considered yang because its organs transport turbid qi. The small intestine and bladder also provide heat needed for proper transport and transformation of food qi.
Shao yin is a yin energy because it stores jing. Heat rules in shao yin because it contains the imperial true fire necessary to warm and move the true Water. The heat in shao yin is comparable to the brilliance of the sun. Yet it is dependent on the yin blood to be strong.
The heart is the ruler of the twelve channels. Its position is south, its season is summer, and its nature is fire. The heart represents the body’s imperial fire.
The heart is the root of life. It is the seat of the spirit, the master of blood and vessels. It is the most important organ because of the spirit which resides in the qi which is anchored in jing. Jing is also known as blood.
The heart is connected to the kidney. The heart resides in the vessels. It rules the kidneys because it is the master of all organs. The kidney true water must be abundant or the heart fire will flare out of control.
The yang qi of the body is like the sun. If the sun loses its brilliance or illuminating effect, all things on earth become inactive. The sun is the ultimate yang. This heavenly energy of the sun, yang qi, surrounds the earth. Correspondingly, in the body this means that the yang qi circulates around the center or core and has the functions of protecting the body.
Yin is the essence of the organs and the fountain of the qi. Yang protects the exterior of the body against pathogens and makes the muscles function. When the yin fails to contain the yang, the flow in the channels will become rapid, causing the yang qi to become excessive and reckless. If the yang qi is deficient and unable to counterbalance the yin, communication between the internal organs will be disrupted, and the nine orifices will cease to function. When the yin and yang are balanced the true zhen qi becomes unshakable, and pathogens cannot invade.