It is a concept in Eastern philosophy symbolizing the origin of all things and the essence of the universe.
It represents the harmonious coexistence and continuous change and circulation of two opposing forces, Yin (陰) and Yang (陽). The emblem in the center of the Taegeukgi (Korean flag) is a depiction of this Taegeuk.
The SeungNiJeDan (Victory Altar) claims that the universe was originally in a neutral state (WonGeuk), but was shattered due to the properties of Yin and Yang to become the current state of the universe, the TaeGeug state, and that it will be restored to a neutral state (HwanGeuk) through the Messiah.