Kashiwaya Sensei from the Seattle Ki Society visited my first dojo...many many years ago.
Ron...no old age jokes please!!!!
This very question was raised. When one has a partner in class that has a Karate type background and snaps the punch back after a strike, how does an Aikido sudent deal with that.
Kashiwaya Sensei gave two very good answers. One said stay put...one said enter. Ya...we were all confused!! But he detailed what he meant after he were all looking at him with blank faces...
Ted (range) and Ron(timing) made both of Kashiwaya Sensei's points. If you keep good distance Uke must step in deeply enough to reach you. And by doing so, Uke enters your universe and most times will leave an opening that can be exploited.
And Ron mentioned timing. Kashiwaya Sensei demonstrated that if one is relaxed enough,
(No Ron...I do not mean taking a snooze relaxed!!! :-)) Nage can see Uke's intent and be waiting for the return of the strike already at Uke's side. He demonstrated both techniques wonderfully. And as it was back in the mid 1990's.....of course I forget!! But it helped me to understand that both keeping correct range and having timing(and I do not mean REACTION timimg....I mean PROACTION timing) are very important as one studies Aikido.