A difficult question to answer. Difficult because I know the answer will be misused by people not sympathetic to our training methods.
Fast answer is there was very little “sparring” in the dojo back in the 1970s.
The classics, when done the way they were practiced in the 1970s, were applied as a flow of such abuse that there was little opportunity to “bounce back” with a reply technique. Hits to limbs and joints were immediately followed by ripping grabs to secure and unbalance, followed by unsportsmanlike head-butts and pull-downs into ground locks and finishes. Takedowns invariably involved joints being driven into the floor with knees, fish-hook pulls into the cheek, and windpipe crushes with the fingers.
The classics were developed to deal with a fully committed adrenaline-soaked murderous battlefield assault. Boom – the guy is 100% on you. There is no room for the set-up or “feeling out” that permits effective sparring as I experienced in my time of competition karate, wrestling, and kickboxing years ago. A major part of this 100% assault is the psychic energy that explodes out from an aggressor who is freight-train direct in his absolute lack of self-referencing awareness and complete imperviousness to any thought of possibly being harmed himself. It’s the, “I won’t ‘spar’, but I will chew your ears off as I kill you,” kind of maniacal intention that happens in wars.
Yes, I know that answer is not popular with young martial artists enamored of MMA/BJJ competitive training today. But all I can say is that the severity of the pain and the directness of the onslaught did not allow much back-and-forth that one might associate with boxing or judo or wrestling training.
And… in another post I will give my views on why we now choose to do more “freer style” training in our To-Shin Do dojos today, even though that was not the way I was taught in Japan 40 years ago.