Increasingly, body movement open handed (or tai jutsu) in our training include atemi because it gets the attacker to move, and puts you in a better position to control the attack and get behind, or in a position where you can't be hit. Sometimes it's just the threat of quick movement that gets the uke to react. In this split second, you can take their centre and throw them.
Moving our body into the ukes space, as we take their centre is an evolved form of aikido that looks very simple. Attack and defence become one in the more advanced forms and we can test many of the techniques with a bokken to verify the direction and intent of our defence.