The excavated archaeological finds have proved that about 4000 years ago in the era of the reputed founder of the hsia dynasty the eight diagrams experienced evolution from the double diagrams to the single diagram , and that the eight diagrams had entered the period of development from its embryonic form 到了四千年前的夏禹时代，从出土的文物考古资料中证明：八卦由单卦到重卦，经历了孕育雏型期之后，至此已经进入了它的发展演变期了。
