Inyoka (the Yin and Yang School of Philosophy) (陰陽家)
Inyoka is a philosophy group regarded as one of Shoshi hyakka (the Various Masters of the 100 Schools: Thinkers of Ancient China), and one of the six major schools. Inyoka taught the yin yang concept, in which the generation and change of everything in the world were categorized into two types, yin and yang. The representative thinkers include Zou Yan (騶衍 or 鄒衍) and Koson(公孫発). Later, at the end of the Warring States Period (in China), it was incorporated with Gogyo shiso (Five Elements Theory), and it spread across the East Asian cultural sphere as Inyo [Onmyo] gogyo shiso (Yin-Yang Wu-Hsing Idea).