Mushin is a Japanese term; English translation "no mind") is a mental state into which very highly trained martial artists are said to enter during combat. They also practice this mental state during everyday activities. The term is shortened from mushin no shin is a Zen expression meaning the mind without mind and is also referred to as the state of "no-mindless". That is, a mind not fixed, or occupied by thought or emotion and thus opens to everything.
Mushin is achieved when a person's mind is free from thoughts of anger, fear, or ego during combat or everyday life. It is my opinion that to achieve this state of mind should be every martial artist goal. I myself enter the no mind state quite often, during my training sessions. I wonder if any of my fellow martial artists have.