Four seas

The sea of marrow, sea of blood, sea of qì, and sea of grain and water. The Magic Pivot (灵枢 líng shū, hǎi lùn) states, People have four seas... the sea of marrow, the sea of blood, the sea of qì, and the sea of grain and water. The stomach is the sea of grain and water... The thoroughfare (chōng) vessel is the sea of the twelve channels... Chest center is the sea of qì... The brain is the sea of marrow. The four seas can be regulated at specific points on the body: the sea of marrow at GV-20 (Hundred Convergences, 百会 bǎi huì) and GV-16 (Wind Mansion, 风府 fēng fǔ); the sea of qì above and below the pillar bone (collar bone) and at ST-9 (Man’s Prognosis, 人迎 rén yíng); the sea of grain and water at ST-30 (Qì Thoroughfare, 气冲 qì chōng), and ST-36 (Leg Three Lǐ, 足三里 zú sān lǐ); and the sea of blood at BL-11 (Great Shuttle, 大杼 dà zhù), ST-37 (Upper Great Hollow, 上巨虚 shàng jù xū), and ST-39 (Lower Great Hollow, 下巨虚 xià jù xū).