Re: The Iron Hand Technique ( Illustration )
Nice illustration and interesting concept. After spending many years doing striking arts and delving into the realm of hand (and body) toughening, I can atest to this kind of scarring (I suspect the 'callous' is really scar tissue).
I gave the conditioning up after some years though, and now view it as a bit counterproductive.
The human hand (and the human body) is quite a bit tougher than we think, and most feats of breaking and such are really more slight-of-hand, confidence and good physics than they are the result of iron-hand conditioning. That's just MHO, others' mileage may vary.
I don't buy into the concept of ki or chi as used by some martial artists (friendly wave to Mike!), but the idea of using the allegory of ki/chi to engage proper ergonomics and to develop a confident and focused mindset are perfectly on target.
The strikes we use in the system I study do not rely on conditioning, but one what we call a wave effect, using extension and contraction to create a soft/hard hand. It's way more complex than that, but not particularly mystical. It's, as I said, good ergonomics and physics.
I've known some old budo guys and folks from other martial traditions who've done extensive conditioning and almost invariably (there are a couple of exceptions, as there are to almost all generalizations), they wind up nearly crippled if they continue the process for many years.