Trigram for Fire

A solid line, a broken line, a solid line: fire.

In the I Ching, a solid line is yang (firm, active) and a broken line is yin (yielding). Every possible stack of three gives the eight trigrams. ☲ has two firm lines outside and a soft one in the middle, which classical commentary reads as a flame: bright on the outside, empty at its heart.

Its name, Li (離), carries the ideas of brightness and of clinging, since fire must cling to fuel to burn; the well-known Wilhelm translation calls it "the Clinging". The traditional associations include the sun, lightning, the eye, beauty and the middle daughter, and in the most common arrangement it stands for the south.

Two trigrams stacked make one of the 64 hexagrams that I Ching readings are built on. ☲ doubled is hexagram 30, also called Li. In feng shui, the trigram appears on octagonal bagua mirrors and maps.

Why is ☲ on South Korea's flag?

It is Ri, fire, one of four trigrams on the Taegeukgi.

South Korea's flag, the Taegeukgi, shows a red-and-blue taegeuk (the yin-yang circle) with four black trigrams at the corners: ☰ heaven top left, ☵ water top right, ☲ fire bottom left, ☷ earth bottom right. Opposites face each other across the circle, so fire sits diagonally from water. The design dates from 1883. In Korean the trigram is read Ri (리).