The Four Bigrams

A combination of two bits, when represented by a gua figure, is called a bigram.

In the second split of the cosmic egg, the opposition of yin and yang is accompanied by the opposition of pure and mixed.

	yin	yang
pure
mixed

In the shape of , the passive element rests above the active element. This condition is unstable: the nature of yang is to move, while the nature of yin is to fall down. A far stabler condition would be . Because of this contrast of stability, is dominated by yang and with yin.

The "dominance" is determined solely by the line in the bottom position. Therefore, the bottom position is more significant than the top position.

Some possible associations based on the associations derived for the two monograms:

Bigram	Binary	Decimal	2D direction	Wind direction	Color	Hellenistic element
	11	3	up	south	blue	air
	10	2	left	east	red	fire
	00	0	down	north	yellow	earth
	01	1	right	west	green	water

Pure yang and yin have been chosen to represent "up" and "down" because they are slightly less subjective and therefore more profound ideas than "left" and "right".

Note: in the traditional Yi Jing, is associated with yang ("young yang") and with yin ("young yin"). This can be justified by associating the top position with young/present/future and the bottom position with old/past.