The Yinyang concepts originated in the Fourth Century BC and explained natural phenomena as the 'ceaseless rise and fall of opposite yet complementary forces'.  Yin and Yang are strictly translated as the shady side of a hill (Yin) and the sunny side of a hill (Yang).

The Yin qualities of cold, interior, dark and potential and the Yang qualities of light, heat, exterior, rising and activity exist in relation to each other.

Yin and Yang are continuously interacting, and are interdependent and transformative of each other.

A dynamic balance of Yin and Yang is characterised by health; an imbalance by disease. 

This characterisation of phenomena into two aspects of correspondences (Yinyang) was further expanded in the Five Element system, the intrinsic part of Traditional Chinese Medicine.

The Five Elements represent the universal consistency of systematic links.  The Laws of Nature direct all movement within these five elements. 

Nature and Man are the macrocosm and the microcosm of these Laws.  These Laws organise the movement of Qi (Chi) within the individual and provide the structure for diagnosis and treatment in the Five Element system.