Yin and Yang
The concept of Yin and Yang became popular in the 3rd century BC. A school of naturalists and philosophers conceptualised the notion of yin and yang and the Five Element Theory. The school was known as 'The School of Naturalists' or the 'School of Yin-yang'. According to the Yin Yang principle, all life on earth went through five phases (wuxing) - fire, water, metal, wood, earth - which continuously interchanged with each other. (Further reading: go to School of Naturalists)
In Chinese mythology, Yin and Yang were born from chaos when the universe was first created and they are believed to exist in harmony at the centre of the Earth. During the creation, their achievement of balance in the cosmic egg allowed for the birth of Pangu (or P’an ku), the first human. Further reading can be found at Ancient History website.
Yang energy is denoted by the white part of the circle. Some of its characteristics include:
Yin energy is denoted by the black part of the circle. Some of its characteristics include:
These are certainly not finite lists, as the opposing forces are at work in all aspects of our lives. There is no 'best' energy. Too much of Yin, or too much of Yang would bring imbalance to our lives. Yin and Yang are constantly interchanging, and are reliant on each other to maintain balance and harmony. They should be seen as complementary forces, rather than opposing forces. You will notice this balance is symbolised by the black dot within the white, and the white dot within the black. There is some yang within yin, and some yin within yang.
Yin and Yang feature in Chinese Medicine, with the limbs and anterior and posterior muscles having yin and yang characteristics.