Re: Sempai kohai differences
I agree with the commentts that have been made so far.
The most difficult partner is not the "noob" but the the partner who uses his/her strength to counter techniques . This does not allow one to learn the technique but becomes a battle of strength instead. Then the practice turns into an isometric workout.
The "nob" who moves differently from the "expected" teaches you how an non-practitioner would move.
That's my 2 cents worth.