The flag of South Korea, or Taegeukgi (also spelled Taegukgi in convention) has three parts: a white background, a red and blue taegeuk (also known as Taiji and Yinyang) in the center, and four black trigrams, one in each corner of the flag. These trigrams are carried over from the eight trigrams (Ba gua), which are of Daoist origin. Taiji, trigrams, and Taoism, which originated in China, are parts of the Korean Culture.
The flag was designed by King Gojong or Pak Yeong-hyo in 1882 by the deletion of four of these trigrams, and Taegeukgi was adopted as the national flag of Joseon Dynasty on March 6, 1883.
After independence, both North and South Korea adopted versions of the Taegeukgi, but North Korea changed its national flag to a more Soviet-inspired design after three years.
The Constituent Assembly of the Republic of Korea (South Korea) adopted the Taegeukgi as the national flag on July 12, 1948. After the establishment of the government of the Republic of Korea, “The Rules for the Flag of the Republic of Korea” were first enacted.
The white background symbolizes “cleanliness of the people”. The Taegeuk represents the origin of all things in the universe, holding the two principles of yin and yang in perfect balance—the former being the negative aspect rendered in blue, and the latter as the positive aspect rendered in red. Together, they represent a continuous movement within infinity, the two merging as one.[clarification needed]
The four trigrams are described in this table:
Source Wikipedia: http://en.wikipedia.org/wiki/Flag_of_South_Korea