Every national flag probably has a lot of meaning behind it. And while the Republic of Korea’s flag might look simple, the taegeukki, 태극기, is packed with meaning.
To view the taeguekki, it’s a white background with a red and blue taegeuk, 태국 (aka, the Chinese yin-yang symbol), in the middle and four trigrams made up of black lines in the corners. But when you really understand the symbolism behind it, it’s so much more.
The white background symbolizes the country or its people. The taegeukki symbolizes the universe showing the negative in blue and the positive in red in perfect balance. And the four trigram symbols each have multiple meaning, representing nature, seasons, directions, virtues, family, and elements. (You’ll find a great chart of the meanings ascribed to each trigram here: http://en.wikipedia.org/wiki/Flag_of_South_Korea).
The flag was first adopted in the 1880s, as Korea began to have more contact with other nations. But the symbol was banned during the Japanese occupation (1910-1945) and ownership of the flag was punishable by execution. Despite the ban, Koreans continued to honor the taegeukki and it became a symbol of resistance and independence during the occupation.
Once liberated from Japanese occupation, both North Korea and South Korea initially adopted the taegeukki as their flags. But three years later, North Korea changed its flag to a design that more closely matched the flag of the USSR.
Of course, over the years the flag has undergone some changes although the general design has remained the same. I found this cool graphic showing the taegeukki through the years. You can see the original of this flag collection, as well as an interesting graphic that details the meanings of the taegeukki’s symbols, at the KoreanClass101 blog. You’ll find that address below. (http://blogs.koreanclass101.com/blog/2008/12/23/the-other-red-white-and-blue-the-south-korean-flag)