NOT the simple story. Getting the basics right in the beginning.
For thousands of years (and before) the Chinese have used the idea of yin and yang to explain reality. It is the versatility of this idea which has kept it alive for centuries. Yet it is close enough to similar ideas in other cultures as to be mistaken for what it is not. One of the first things to realize is that yin/yang is a series of complementary not antagonistic opposites. For instance, you can use yin and yang to mean feminine and masculine but NOT good and bad. The yang version of a liberal is NOT a conservative. Matter and energy complement one another, right and wrong do not.
That said we can use yin and yang to more easily grasp the important principles of Qigong. We may see the act of inhaling as yin and exhaling as yang. Or we might see them as reversed. Is that confusing? It shouldn’t be. Women, for instance, are not just yin. It is femininity that is yin. How close a woman comes to femininity is the measure of yin. This or that woman might actually be more yang that most men (a not uncommon occurrence). A breath, going in or out, is neither yin nor yang but derives its meaning from context. Are you performing a violent inhalation just as your head breaks the surface of the water? Or are you inhaling gently before you place your lips on the blow gun?
Let’s take an example that will come up in almost every study and type of Qigong you will ever practice…