No Trace

In order not to leave any trace when you do something, you should do it with your whole body and mind; you should be concentrated on what you do. You should do it completely, like a good bonfire. You should not be a smoky fire. You should burn yourself completely. If you do not burn yourself completely, a trace of your self will be left in what you do. You will have something remaining which is not completely burned out, with nothing remaining but ashes. This is the goal of our practice. That is what Dogen meant when he said, "Ashes do not come back to firewood." Ash is ash. Ash should be completely ash. The firewood should be firewood. When this kind of activity takes place, one activity covers everything.

(Shrunyu Suzuki, Zen Mind, Beginner's Mind)