The on-yo-do philosophy named comes from the Chinese principle of yin and yang. People in ancient China discovered five natural elements: wood, fire, earth, metal and water.They thought that these five elements could explain everything concerning the universe and human life. These five elements were also combined with the principle of yin and yang to form philosophy. The words yin and yang mean negative and positive, and they are the opposites of each other. This philosophy was introduced to Japan in the sixth century, and the Japanese people came to know it as on-yo-do. On-yo-do explained natural phenomenon and told people’s fortunes.