Irimi

In Japanese martial arts, Irimi (入り身) is the act of entering straight into a technique, as opposed to the more indirect entrance into technique called tenkan. In basic training, irimi usually looks like a step forward, straight or at an angle but usually ending with the body facing the attacker, rather than in the direction of the step. To enter with irimi, the defender needs to move in the very moment of the attack or even himself initiate it.