When the Great King Sejong invented Hangul, he had in mind the two basic principles of the yin-yang cosmology of eastern philosophy.

    Vowels Graphemes
    The vowels were designed on the basis of The Three basic components of the universe which are Heaven( ), Earth , and Man. Heaven( ) represents the circular shape of heaven, Earth represents the flatness of the earth, and Man expresses the standing position of a human being.
    [8 hexagrams]
    The vowels were designed on the basis of of Eastern philosophy.

    King Sejong designed the HANGUL consonant letters so that their shapes would reflect the place and manner of articulation of the consonant sounds.
    The shapes of five basic consonants suggest the five basic types of articulation, as follows.
    The other 14 consonant letters are derived from these by adding strokes.