This symbol depicted in the middle of the South Korean flag represents the “Cosmic Egg” containing the grain from which all the manifestation of the Cosmic world will come out. It primarily represents the fundamental polarity between celestial (red) and terrestrial (blue) aspects, between what the Chinese tradition calls Heaven and Earth, the igneous (red) and humid (blue) principles or, more generally, yang and yin. Yang is associated with light, to clarity, to active principle or Heaven; yin is related to the dark side, to obscurity, to passive principle or Earth.
Bearing all oppositions and complements proper to the manifested world, the yin-yang symbol represents here the union of the two indissociable yang and yin principles, the “Supreme Top” (Taiji), the “First One” or the Primeval Principle at the origin of the whole manifestation.
The fact that usually yin precedes yang within the symbol denomination simply means that the human being is living his terrestrial states (yin) before re-discovering his spiritual or celestial state.
Considered as distinct in terms of a polarity, yang and yin are respectively represented by a solid line () and a broken line (). The superposition of three of these lines provides a trigram, read bottom up according to three levels (terrestrial, human and celestial). The human being takes up an intermediate position between Heaven and Earth because he has to discover, at the same time, his celestial source (the world within himself) and his place within the terrestrial world (himself in the world).
Combined according to the three levels, the solid and broken lines give birth to eight trigrams (23), four of which are taking place on the South Korea flag.
Yin-yang symbol and trigrams
The link between the “Primeval One” (Taiji), source of yang and yin distinction and its diverse manifestations within the trigrams, may be condensed in the following diagram:
The trigrams may also be designed in circle, an arrangement attributed to Fu hi, in order to enlighten their complement in respect to the yin-yang symbol:
The polar complement of yang and yin characters is effective for each of the three levels of the trigram as shown on the above diagram. For more details on the trigram arrangements and their meanings, consult the trigrams.
As already mentioned, the South Korean flag keeps only the trigrams, which are connected to the two main axes.
The vertical axis associates Heaven characterized by three solid lines (yang) and Earth, composed of three broken lines (yin). They respectively represent the yang and yin fullness. Between these two extremes, stand the other trigrams where yang and yin are combined in different proportions to symbolize the development of the whole manifestation of the “Cosmic Egg”.
The horizontal axis links Fire, igneous or celestial symbol, to Water, humid or terrestrial symbol. Fire, by nature luminous and hot (yang), sparkles around a less bright heart (yin) whereas Water, by nature dark and cold (yin), has the capacity to absorb light and heat (yang). So, Fire is represented by two solid lines and a broken line hemmed in, whereas Water associates two broken lines and a solid line in its middle.