The traditional hanbok was based on three shapes that signify the foundation of the universe "samilshingo." The shapes were the circle "won" that symbolized heaven, the square "bang" that symbolized earth, and the triangle "kak" that symbolized man. The circle is related to the number "one," the square to the number "two," and the triangle to the number "three." The unity of the three shapes is called "han." These three shapes are symbolized in the hanbok: the waist is the circle, the legs and sleeves are the square, and the hip or torso area is the triangle. In comparison to the principle of Eum-Yang, the trousers are Eum or earth, the jacket is Yang or heaven, and the belt is man, who ties everything together.
Traditional dobaks were all white in color to symbolize oneness with the universe "han." . Some organizations have adopted different color schemes on seams and lapels on their tobaks to differentiate between the color belt ranks, black belt degrees, and instructor status.