A tai yang wind pattern can manifest as tai yang wind strike or tai yang wind cold. The difference is the amount of cold closure and sweating on the surface.
Tai yang represents all the yang qi on the surface and in the interior. There are many references to this in the Yellow Emperor’s Classic. Tai yang connects all the yang in the body. The acupuncture point Dazhui Du-14 is this connection.
Plain Questions Chapter 31, The tai yang channel controls the surface of the body. Its channel connects with all the yang channels in the body. Therefore tai yang is also considered a governor of the yang qi.
Clear qi is yang and turbid qi is yin. Clear qi disperses over the body and yin qi nourishes the organs. Clear pure qi strengthens the extremities and the turbid qi is transported out of the body.
Plain Questions Chapter 5, The clear yang qi disperses over the surface of the body, the turbid yin qi flows and nourishes the five zang organs. The pure yang qi expands and strengthens the four extremities, and the turbid yin qi fills the six fu organs.
Yang fire is the functional aspect of the body. Yin water is the nutritive aspect of the body.
Plain Questions Chapter 5, The elements of fire and water are categorized into yang and yin, the fire being yang and the water being yin. The functional aspect of the body is yang and the nutritive aspect is yin.
In a tai yang pattern the yang qi is damaged, meaning there will be less of it to govern the surface and the interior, which gives rise to excessive sweating and or no sweating. The different patterns that can arise can best be seen on a spectrum. This range of patterns goes from excessive heat formation to excessive cold accumulation.
A pattern in the middle of this range will present with a mixture of cold and heat. When this happens the surface becomes half open and sweating occurs, or half closed which prevents sweating.
In the Shang Han Lun tai yang formulas can be organized around this concept.
An example of a formula where the surface is closed is ma huang tang. In this pattern of tai yang wind cold there will be no sweating. It is the ma huang that strongly tonifies the heart yang is increase the yang circulation to clear the excessive cold.
An example of a formula where the surface is closed is da qing long tang. In this pattern of tai yang wind cold there will be no sweating and excessive heat. The heat accumulates because it can not be regulated or expelled. It is the ma huang and shi gao that promote the dispersing of heat and opening of the surface.
An example of a formula where the surface is open is gui zhi tang. In this pattern of tai yang wind strike there will be sweating. It is the gui zhi that restores the function of yang qi to control the skin to stop the sweating. It is the bai shao that nourishes the yin needed to anchor the yang to keep it from becoming reckless.
An example of a formula where the surface is half open and half closed is ge gen tang. In this mixed pattern of tai yang wind cold and wind strike there will no sweating and sweating. It is the ma huang that clears the cold to promote sweating. It is the gui zhi that restores the function of yang to stop excessive sweating. It is the ge gen and bai shao that nourishe the yin to anchor the yang to keep it from becoming reckless.
In the formula gui zhi ma huang ge ban tang the surface is half open and half closed. In this formula there is more cold than sweating.
In the formula gui zhi er ma huang yi tang the surface is half closed and half open. In this formula there is more sweating than cold.
A half open and a half closed pattern means that yang qi has become weak in the presence of excessive cold. The question is how much of each do you need to treat to restore normal function.