The Middle Dantian is located within the Tan Zhong acupoint, which is at the chest area; it serves as a storage location for magical power during the Qi Cultivation Stage.
The Lower Dantian is located at the Guanyuan acupoint, three inches below the navel.
The Upper Dantian represents the divine spirit.
The Middle Dantian represents Qi.
The Lower Dantian represents essence.
During the Qi Cultivation Stage, cultivators have their magical power stored in their Middle Dantian, while mortal martial artists can store their true Qi after practicing mortal cultivation techniques in their Lower Dantian.
During Foundation Establishment, the Upper, Middle, and Lower Dantians all undergo changes.