San Jiao

三焦 sānjiāo (triple heater) is the solid, yin organ (藏 záng) related to the ministerial fire phase.

It is said to have “a name but no form” and described as the opener of channels, from which waterways originate.

San Jiao channel herbs have been associated with the meridian network; or the upper, middle and lower sections of the trunk; and are responsible for maintaining a constant temperature throughout the body using the regulation of water to distribute the warmth of heart and kidney fire and to drain excess.

Its yin–yang property is considered lesser yang (少陽 or 少阳 shǎoyáng).