When it comes to the question of resisting or not resisting while practicing Aikido I propose a simple rule: Your body should resist, your mind shouldn’t. What does that mean? Being a good uke (the attacker) in Aikido is actually more difficult then being nage (the person who is doing the technique). To be a good uke you not only need good coordination, but your mind must be free from the past, so your body acts spontaneously. Being free from the past means that you attack as if you don’t know the technique nage is doing. In a way you simulate a naive attacker, who does not know anything about Aikido. Only then you will discover if a technique works or not. If you leave your past knowledge behind and just attack, you accept the lead of nage and your movement and the movement of nage will be in harmony. If nage does the technique correctly, no resistance will happen. If the leading movement is not correct, your body will resist naturally without your intention. This is correct resistance which benefits the development of the technique. Another, more subtle form of resistance is premature following, or what Yoshigasaki Sensei often critizised as „being too nice“. This is the resistance of not accepting the lead of nage, but doing your own thing instead. For example you fall down before nage really throws you, or you fall down even if the movement was wrong. This form of resistance may feel „nicer“ for nage, but is actually as detrimental to the development of the technique as willfull physical resistance. Even with beginners you should not just fall down to give them a good feeling, but help them to lead correctly by assisting them with your movement.
Klaus Heß 07/2021 (translated with DeepL)