Heart

心 xīn is the solid, yin organ (藏 záng) related to the sovereign fire phase. It is the basis of life, compared to the ruler of the body, which stores the spirit (神 shén).

It generates the Blood, manifests in the blood vessels and is visible in the complexion of the face. It opens into the tongue. It also controls sweating, as sweat is derived from Blood.

Its yin–yang property is considered lesser yin (少陰 or 少阴 shǎoyīn).