when these two forces were at work in harmony; life was what it should be.Yin andyang are opposite in nature, but they are part of nature, they rely on each other, and theycan't exist without each other. The balance of yin and yang is important. If yin is stronger,yang will be weaker, and vice versa. Yin and yang can interchange under certainconditions so they are usually not yin and yang alone. In other words, yin can contain
