... the continued state of mental alertness and physical readiness to instantly attack or respond to an attack or counter attack by ones opponent.The kanji's are 残心 (Zan-Shin). Zan (残) means residual or remaining; Shin (心) means heart or mind. So the literal translation would be something like the remaining mind. Of course, as we know, it is used in the world of martial arts, but in a general way, it is simply the state of mind after one has performed a task. In kendo, one teaches that Zanshin should be the alertness after a strike, accompanied by clear physical postures and movements to manifest this state of mind.
For me, however, I think there is an element of "declaring victory" for the attack just made. This goes to the aesthetic part of kendo. When I execute Zanshin, I want to show with my kiai and movement: "I wanted it, I went for it, and now I am claiming it!"
What is Zanshin for you?