Danjeon (丹田, Tantien in Chinese, Tanden in Japanese) is located at the lower abdomen, 2-3 inches below navel and in the middle of the body.
It is the source of the life energy of the human body and the starting point of all meridians in human body. It is not actually a physical organ, but an elixir field. It is somewhat similar to the idea of manipura, the seat of prana in the yoga tradition. Sun Do exercise is mainly focused on development of this energy center through its breathing methods and exercises.
For the ordinary person it is not easy to understand Danjeon, but we naturally focus on the Danjeon while holding the breath when we need extra physical strength. Also, babies’ breathing is natural Danjeon Breathing. Their lower bellies rise up and down as they breathe. Expansion and contraction of the lower abdomen is typical of natural Danjeon Breathing. Danjeon Breathing is the way of bringing us the peace and fresh life energy of young children again.
There are three (3) Danjeons. The energy center located at lower abdomen is called the Lower Danjeon, the energy center located at the brain is the Upper Danjeon, and the energy center located at heart is called the Middle Danjeon.
The energy in the 3 Danjeons can be transmitted between each other, but the Lower Danjeon is the only place where the life force is formed through Danjeon breathing.