Zanshin means to do each thing completely. Doing this does not mean to stick and hold. Sometimes, in sitting, you find yourself lost in a thought and then you wake up and cut the thought; then you find yourself going back to check if you've cut that thought. But that thought is gone and you are only trying to find a definition of yourself, you are only trying to become someone who has "cut the thought." Instead, when you wake up from the thought, that's it. What now? Zanshin then means, a mind of continual readiness, like a mirror ready to reflect whatever is shown to it.
In the martial arts, Zanshin means having no break in our activity, because there is no time to take back a stride or block and fix it. It also means going beyond technique, because we cannot force the situation to conform to the technique. The angle of the strike and the force of the strike must be adjusted immediately to the energy of the partner.
In practice we must go beyond strategies of defense and hesitation. We must open up to the energy of mind itself as it expresses itself as seeing, hearing, touching, tasting, smelling and thinking. Penetrating into this energy, we must go beyond all barriers.