Objects depicted on the flag symbolize much of the thought and mysticism of oriental philosophy.
The circle depicted on the flag, the eum-yang (shown on left), is divided equally, and is in perfect balance. Its origin is based on the oriental philosophy of eum-yang (known in China as Yin-Yang). It was originally thought that this philosophy was developed in China by Chou Fung-i (1016-1073 AD), a metaphysical philosopher of the Sun Dynasty, who published his theory of tai-chi in 1070 AD and supposedly designed the tai-chi (Yin-Yang) symbol. However, a piece of stone with the eum-yang (Yin-Yang) symbol carved on it was discovered at the site of the Korean Buddhist temple Kam-Eun, which was built in 682 AD. This is the oldest known use of the eum-yang symbol. This discovery indicates that the symbol was in use in Korea as early as 682 AD, well before Chou Fung-i was born.
The eum-yang symbol expresses the dualism of the universe, the perfect harmony and balance among opposites, and the constant movement within the sphere of infinity. An example of dualism may be expressed in the upbringing of a child. There are two opposing methods to raise a child: praise or punishment. Praise is considered good and punishment is considered bad, but both are needed for a proper upbringing. However, too much of either may cause behavior problems with the child. There must be balance and harmony between the two extremes to ensure the child is brought up properly.
Eum (blue portion of the symbol) means dark, cold, or negative, while yang (red portion of the symbol) means bright, hot, or positive. A very old Chinese book called Choo-Yuk claims that all objects, through the movement of yin (eum) and yang, express events by their dualism. For example, the moon is eum, the sun is yang; the earth is eum, the sky is yang; night is eum, the day is yang; and the winter is eum, the summer is yang. Eum and yang are relative. Therefore, "A" can be eum with respect to "B" while being yang with respect to "C." For example, the spring is eum to the summer yang while also being yang to the winter eum. Eum and yang complement each other. Neither exists of itself alone, they must exist together. To appreciate beauty, you must have ugliness. What benefit is good (yang) if evil (eum) does not exist?
Lao Tsu (known No Ja in Korea), a famous Chinese philosopher who founded Taoism, wrote a chapter on dualism in his book Tao Te Ching. The following is a summary of the chapter:
Under heaven all may see beauty as beauty only because there is ugliness. All may know good as good only because there is evil. Therefore having and not having arise together. Difficult and easy complement each other. Long and short contrast each other. Front and back follow one another. Therefore, the sage goes about doing nothing, teaching no talking. The ten thousand things rise and fall without cease, Creating, not possessing, Working, yet not taking credit. Work is done, then forgotten, Therefore it lasts forever!
When looking at the two comma-shaped sections "ukwdrops" in the eum-yang symbol, the thicker part of a section indicates the beginning and the slender part indicates the end. The eum begins where the yang gradually vanishes and vice versa. The red section is always on the top half of the circle.
The harmonious state of the movement of eum-yang is called tae-guk in Korean (tai- chi in Chinese). In Korea, the flag itself, is called Tae-Guk (the origin of all things in the universe) or Tae-Guk-Ki ki means flag). Tae-Guk is also known as the flag of "great extremes."
While the circle represents dualism, the four trigrams at the corners of the flag (called "gwe" in Korean) represent the four points of the compass, the concept of opposites and balance, and the government. The book of I Ching (Book of Changes), called Yeok in Korean, illustrates 64 trigrams, but the four used on the flag represent the essence of the Dao philosophy of the complete circle of life. Western people are probably familiar with the concept of Karma, or "What goes around comes around." Both Dao and Confucianism thought the family was the center of society. The family, and ones role in the family, determine ones position and role in society.
The upper left and lower right trigrams on the flag are "heaven or father" and "earth or mother" They represent the head of the family. Without them, there is no family. Without the family, there is no society. The upper right and lower left trigrams are "water or daughter," and "fire or son." Together the four trigrams express the mysteries of the universe, and they also represent the family: father, mother, daughter, and son. Confucianism thought these four elements made the perfect family. A family with these four parts had perfect balance (eum-yang). The symbols are placed in a circle to represent the circle of life (the endless cycle of birth, death, and rebirth) and the continuing nature of the universe. South Koreans have many different interpretations the traditional symbols, the following are but a few of them.
- Location: Upper left
- Nature: Sky
- Season: Spring
- Direction: East
- Virtue: Humility
- Family: Father
- Element: Metal
- Description: Justice
- Known as: The creative one
- Represents: Represents bright sunshine when the sun is in the South and its light that makes things grow.
- Meaning: All three lines in the trigram are solid representing the completeness of life. As heaven is greater than the earth, this trigram is first on the flag. The fathers concern for his family is greater than just earthly survival.
- Location: Lower left
- Nature: Sun
- Season: Autumn
- Direction: South
- Virtue: Courtesy
- Family: Son
- Element: Fire
- Description: Wisdom
- Known as: The persisting one
- Represents: Represents fire that gives warmth and light, and dawn and early sunlight as the sun rises in the East.
- Meaning: Trigram is closed at the top and bottom, showing that a son must be well grounded in the heavenly and scholarly ways for his coming role as the father of his family. The centerline is open because the son has not yet fathered a child and he so is viewed as incomplete.
- Location: Upper right
- Nature: Moon
- Season: Winter
- Direction: North
- Virtue: Knowledge
- Family: Daughter
- Element: Water
- Description: Vitality
- Known as: The abysmal one
- Represents: Represents twilight as the sun sets to the West and water, which has no shape or form.
- Meaning: Earth and mothers are the source of life. The top and bottom line of the trigram are open indicating a mother's receptiveness and the incompleteness of life on earth. The center is filled representing the completeness and perfection of motherhood. The role of the mother is to provide for the earthly necessities of life. The top and bottom lines are open representing openness.
- Location: Lower right
- Nature: Earth
- Season: Summer
- Virtue: Righteousness
- Direction: West
- Family: Mother
- Element: Earth
- Description: Fertility
- Known as: The receptive one
- Represents: Represents total darkness when the sun is in the North.
- Meaning: The trigram is completely open. The center is open because she is not yet viewed as fertile, because she has bore no children. The top and bottom are open to represent her coming role as the provider of earthly necessities for her future family. As water flows, when she marries, she will flow out of one family and into another.
The I Ching illustrates the same trigram layout that is depicted on the flag. It shows the eum-yang symbol in the center and trigrams on the sides, but it shows eight trigrams. The other trigrams are "mountain" and "lake", and "thunder" and "wind." Each of the trigrams has a special meaning and are either eum or yang. Heaven and lake are major yangs; water and wind are minor yangs. Earth and mountain are major eums; thunder and fire are minor eums. Originally, there were only five trigrams, one for each of the five elements: water, metal, fire, wood, and earth. They were arranged like a compass, with earth in the center, metal on the left, wood on the right, water at the top, and fire at the bottom.
The white background color of the flag represents the land, the purity of the Korean people, and their peace-loving spirit. Korean people have preferred to wear white clothing; hence, Korea has been called the "white-clad" nation. The eum-yang circle represents the people; the red upper half (yang) represents male and the blue lower half (eum) represents female. Yellow (gold)
During the Joseon Dynasty, official buildings were painted in specific color schemes to denote the social position of the occupant or his office. One color scheme was reserved for the royal class of society "Yang Bang." Unlike western royalty, which is primarily determined by birth, Joseon society permitted a lower class person to advance in class through a series of civil servant exams. This insured that the brightest would be the leaders, regardless of their birth status. When the colors of the Korean flag were chosen, the color scheme of the Yang Bang was used, symbolizing the elevation of all Korean people to the level of the royal class. This concept of a democratic society where all were equal was an idea the Japanese opposed, which increased their opposition to the flag during their occupation of Korea.
Standard color shades of the flag are follows: in the CIE System, the x, y, and Y coordinates for the red are x=0.5640, y=0.3194, Y=15.3; for the blue, x=0.1556, y=0.1354, Y=6.5. Alternatively, in the Munsell System of Color Notation, the red corresponds to 6.0R 4.5/14, and the blue to 5.0PB 3.0/12. In the Pantone Matching System, 186C red and 294C blue are recommended.