Quote from Hatsumi Sensei:
“Takamatsu-sensei used to say one thing repetitively: The heart of Taijutsu is important. And only through training will one polish that heart (like a gem) and understand true Taijutsu. That is why I ask that all those who are fifth dan or above to train with me. Or train with those who ARE training with me, not those that HAVE trained with me. Not the past, the present.”
Ura & Omote 1996.