Move Creation Workshop

[Takanomiya Hijiri]

So, I still stand with my 1200 OM judgement, although I guess it could go up to 1500 OM depending how the variable lightness was ruled.

Nice. Getting something cheaper is always good.

As for the move itself, how does focusing it into a body part affect the move? Does the focused change in mass allow him to punch harder with that one hand, but at the cost of being even harder to control and putting him off balance?

Yeah, just what you'd expect really; he gains a specific amount of weight per second while charging, so putting all of that into just his fist would make a punch more effective than spreading it evenly all across his body, at the cost of messing with his balance, as you said, since one hand would be significantly heavier than the other.
I was trying not to make the description too lengthy, and I didn't want to go into a huge amount of detail on the effects of weight on a human body (I was even trying to avoid including the 'for example' paragraph to start with) for fear of sounding too game-y...
I guess you'd consider that stuff worthy of being included in the description, though?

Lastly, 

Cancelling it returns him to his original weight instantly, but can only be done when he is within 10kg of that weight

It's unclear how he would cancel the move if he's more than 10kg from his original weight.

He'd fall unconscious or die. Those are the only other ways of cancelling it.

If he was heavier than normal, it wouldn't be an issue, of course, since he'd just return to his normal weight (since getting lighter is instant), after which he would cancel it.

If he was lighter than normal, though, then he would have to avoid getting hit long enough to charge up to reach his original weight. If he wasn't able to do so, he'd just not be able to cancel it. Simple as that.

P.S. kg is a measure of mass, not weight *angry physicist screaming*

Oops. I'll change the measurements to lb next time I edit it...

Pounds are a weight measurement, right? :derp: