Lower abdominal center

Danjeon (단전, hanja 丹田) is the Korean term for the lower belly area. A Korean dictionary defines it as a Taoist term (도가) for the part of the body below the navel. It also lists three danjeon: the upper one (the brain), the middle one (the heart) and the lower one (below the navel). Used on its own, the word usually means the lower one.

In kumdo it is described as the body's center, that is, the lower abdomen (아랫배, araetbae). The sources show these uses:

• Movement: according to the Korea Kumdo Association (대한검도회), when moving forward, backward or sideways, or turning, the danjeon (the lower abdomen) must lead, not the feet.
• Breathing: the association's textbook says to breathe naturally with the abdomen (복식호흡, boksikhoheup), deeply, finely and steadily.
• Strength in the lower abdomen: the textbook asks for force in the lower abdomen when thrusting with the bamboo sword (죽도, jukdo), when sitting in the kneeling posture, and when holding the body firm.
• Posture: a beginners' glossary says to keep the shoulders natural and put light force into the lower abdomen (danjeon).
• Holding the breath: the association describes inhaling fully, putting force into the danjeon, holding the breath for a while and then exhaling. In continuous-strike practice (연격, yeongyeok) the breath is held to some degree so the strikes land with full strength.

Beyond kumdo, the lower dantian is also linked to the body's center of gravity and to breathing. Wikipedia describes it as the focal point of breathing technique and the center of balance and gravity.