The flag of Korea refers to the flag of South Korea (Republic of Korea), which consists of a white field with a central blue and red yin-yang symbol, called the taeguk, and four black trigrams, one in each corner. The taeguk in the center represents balance, with the red (top) symbolizing positive forces (yang) and the blue (bottom) representing negative forces (yin). Together, they reflect the harmonious balance of opposites in the universe. The four black trigrams, derived from the ancient Chinese philosophy of the I Ching, represent the fundamental principles of the universe: heaven, earth, fire, and water. Adopted on January 25, 1949, the flag is a symbol of the unity of the Korean people and their efforts toward peace and prosperity.