It's my experience that until someone knows how to use the kokyu/jin forces, they do not really "relax" or stop moving from the shoulders. The essence of the kokyu forces is that they derive their power from either the ground or the weight, allowing the load-bearing responsibilities to shift to the ground or weight and thus relieving the primary muscle-system of the necessity for normal muscular tension.
There is a second, equally-important part of the equation which has to do with the support of the body structure through the myofascial structures and the mind. The myofascial stuff is done through breathing, stretching, held postures like in correct standing practice and/or Akuzawa's stuff, etc. But in a way, you can look at all the breathing and postural stuff as simply being the system with strengthens and increases your abilities with the kokyu/jin stuff. Altogether, it's an extensive and complex system; more so than my summary indicates clearly.
So my answer to your question is "forget the emphasis on "relax" until the principles on using the kokyu forces (aka 'the One Point') are understood".
Trying to "relax" while still using normal strength modes is simply an exercise in frustration and it's about as useful as teaching a pig to sing.