In kendo (Japanese art of fencing), zan-shin refers to bracing oneself to be able to instantly respond to the opponent's attack or counterattack by maintaining the state of alertness; without zan-shin, the attack is not counted as yuko-datotsu (a point) even if it is accurately made against the opponent.
剣道では、意識した状態を持続しながら、相手の攻撃や反撃を瞬時に返すことができるよう身構えていることを残心と呼び、残心がなければ技が正確に決まっても有効打突にならない。