Get to about 1:30min and you'll see how
not to condition your hand if you want it to remain healthy and usable well into old age
[youtube]http://www.youtube.com/watch?v=wD7LH92TDuA[/youtube]
PS: If you saw the karate episode of "The Way of the Warrior" you'll see the karate master using dit da jow he gets from a Chinese master to prevent troubles like that.
But even then, he just applies it a bit, without any massage, greatly reducing the effects of the whole treatment.
IMO all signs the Chinese were very selective of what type of knowledge they passed on to the Japanese.