Where things get complicated are the trigrams surrounding the yin-yang at the center- they represent one of the four classical elements, as well as a whole buncha different stuff- so try and follow me on this:
Upper Left Trigram: 'geon', heaven (nature), spring (seasons), east (cardinal directions), humanity (four virtues), father (family), heaven (four elements), justice (meanings.)
Lower Left Trigam: 'ri', sun (nature), autumn (seasons), south (cardinal directions), justice (four virtues), daughter (family), fire (four elements), fruition (meanings.)
Upper Right Trigram: 'gam', moon (nature), winter (seasons), north (cardinal directions), intelligence (four virtues), son (family), water (four elements), wisdom (meanings.)
Lower Right Trigram: 'gon', earth (nature), summer (seasons), west (cardinal directions), courtesy (four virtues), mother (family), earth (four elements), vitality (meanings.)
And that's pretty much the flag of South Korea- now, moving north, here's the flag of North Korea (official name: Democratic People's Republic of Korea)
The flag breaks down exactly like you'd expect it too: the red star is a universal symbol of communism and socialism and stands for revolutionary traditions. The blue stripes are sovereignty, peace and friendship and the white stripes stand for purity.
That's a little bit vanilla, but the man himself Kim Il-Sung described it this way:
The red color of the flag symbolizes the anti-Japanese fervor, the red blood shed by the Korean patriots and the invincible might of our people firmly united to support the Republic. The white color symbolizes the one bloodline, one land, one language, one culture of our monoethnic country, which lived in purity. And blue stands for the gallant visage of our people, symbolizing the spirits of the Korean people fighting for world peace and progress.(H/t to Wikipedia for this fine, fine quotation.) If revolutionary fervor and twisted ass backwards ideologies are your thing, then for sure for sure, Kim Il-Sung could turn a phrase. And I'll give 'em this: their flag is a hell of a lot easier to break down than South Korea's...
From a design standpoint, I can see the appeal of North Korea's flag. It's clean, it's simple, it knows what it's about- (revolution, socialism, etc), but South Korea focuses you right on the center of things with the yin-yang. The fact that they use a white background means that your eye is drawn to where the color is- and the trigrams arranged around the yin-yang only provide more of a central focus to the overall design which to me, makes South Korea the more interesting flag- especially once you get into the trigrams and their meanings.
But there you go- a timely look at the flags of both Koreas!
Remember, until next time keep your flags flying- FREAK or otherwise!