Zen koans hold an ancient wisdom that anyone can use. On meeting a koan people discover freedom and unexpected openings. The effect is often immediate and surprising. Koans will stay with you, as well. Like a good dog they can follow you around and make you happy in heavy weather.
We usually understand things by taking them up to the top floor of the mind and finding a slot they fit into. Koans are meant to open a different way of being and thinking. Instead of preparing you to understand your life, a koan prepares you to walk through your life.
Koans are concise stories of fundamental predicaments and the way out of predicaments. Most of the time there is a gap between the life we know is possible and the one we live. A koan takes you across any gap between yourself and your life.
There are all sorts of subtle ways to work with koans. It is as if they are independent beings, spirits or animals that have a life of their own and through your interaction with their life your mind is transformed. You can't quite say that they cause the transformation or that it happened because you willed it. You change through your intimacy with the koan. You can't know how change occurs beforehand since that knowing would be with the mind of beforehand. You can just jump in the pen with the koan.
You can notice a few things that seem to be constant. Your truest moment is always here even if you aren't noticing it. Your wisdom is always here too. If you don't search for it, you won't find it. If you do search for it you are thinking that your wisdom isn't here, so again you won't find it. So in the end you are doing something you have no training to do, and no knowledge of how to go about it. You are beyond all your maps, even your maps about you. So what to do? We just jump in the pen with the koan. Wheeee!!