I have to admit I'm puzzled by the frequency with which power is associated with stabbing. I admit it may prove necessary when using a knife with a tip not designed for effective stabbing. But, when a knife has apparently been designed with stabbing/thrusting as a probable task, I tend to think of it as a "touch" weapon.
Sure, change in pockets, belt buckles, etc., will certainly stop or deflect an attempted stab. If the point is very weak, or the thrust is extremely vigorous, then I expect it might break, if it doesn't deflect. Then again, if the user of a knife made for stabbing thinks of his blade as a touch weapon, the attempted targets are not going to be areas where metal may interfere. The same goes for bones. I have no idea how much of the front/side of the human body area is devoted to rib, and how much to the space between. But, if one does not have pinpoint accuracy coupled with an excellent knowledge of anatomy, the rib area just isn't a realistic stabbing target.
The fact that a knife has a point designed for stabbing doesn't by any means mean that it wasn't also designed for slashing as well. If a knife is genuinely sharp, then again, I see slashing as more of a touch effort than a power situation. Sure, adrenaline is likely to play a role. But, these are knives we're talking about. Not broadswords or cutlasses. We aren't like to face much armor. Yeah, leather may offer some real protection against slashing. So maybe if an opponent is wearing leather one uses mostly stabs? Or maybe slashes at areas not covered by leather?
Am I missing something here?