The original EumYang symbol is composed by drawing lines, the length of which are recorded from the measure of the sun's shadow against an 8 foot pole held perpendicular to the ground each day beginning at the Winter Solstice to the Summer Solstice and back again then subtracting the length of the shortest line from all the lines, into a diagram of six proportionally increasing concentric circles divided into 24 equal sectors such that the lines are drawn clockwise from the center of the circle to the perimeter for those lines obtained from Winter Solstice to Summer Solstice and from the perimeter to the center of the circle for those lines obtained from Summer Solstice to Winter Solstice, then rotating the diagram such that the Summer Solstice position is at the top and the Winter Solstice position is at the bottom, then connecting the lines and shading the area described by the lines, and finally placing a smaller shaded circle on the segment of the Summer Solstice and a smaller unshaded circle on the segment of the Winter Solstice each centered between the perimeter and center of the circle.

The shaded area is Eum and the unshaded area is Yang. The Summer Solstice at 0° in the symbol occupies the position of maximum Yang. The Autumnal Equinox at 90° in the symbol occupies the position of minor Eum. The Winter Solstice at 180° in the symbol occupies the position of maximum Eum. The Vernal Equinox at 270° in the symbol occupies the position of minor Yang. Beginning at the position of the Vernal Equinox in the symbol, the Sun Longitude on the ecliptic is 0° and increases 15° with each remaining clockwise sector of the symbol.

EumYang (YinYang) theory has permeated Asian thought since at least the 4th century B.C. as evidenced by the idea of Eum (Yin) and Yang (Yang) included in JwaJeon ChunChuSiDae Zuo's Commentary on the Spring and Autumn Annals (ZuoZhuan ChunQiuShiDai). However, the actual period in which it was first conceived is lost in antiquity. It did not evolve from Do Way (Dao) described in No Ja DoDeokKyeong Lao Zi's Way of Virtue Classic (Lao Zi DaoDeJing). Nor did it evolve from TaeKeuk Great Extreme (TaiJi) described in YeokKyeong Change Classic (YiJing). It is not Do Way (Dao) nor is it TaeKeuk Great Extreme (TaiJi), rather, they incorporate EumYang (YinYang) in their doctrines.

Essentially, EumYang is a "Monistic Dichotomy" or metaphysics for the systematic investigation of the nature of first principles and problems of ultimate reality to include the study of being and structure of the universe. All things correspond to and consist of Eum and Yang. The negative, passive, weak, destructive principle is Eum while the positive, active, strong, constructive principle is Yang. As distinct principles, Eum and Yang interact and counteract each other while Eum and Eum or Yang and Yang activate each other. Although simply stated, its influence has been extensive and its application exhaustive.