Kriegsmesser & Katana Comparisons?

In the old manuscripts about messer techniques you see messers with only a short crossguard like a tsuba too, but swordlike crossbars with a nagel are more typical.
I'm just watching a dvd about messer techniques and many of them use a larger crossguard.
Btw. there is some blade gripping what seems to be not a good idea with a very sharp katana (don't know much about jsa but don't remember ever have seen that).
Pgandy's video shows techniques similar to messer but his dagger is not far away from a shorter messer in lenght.

I don't see why gripping a katana blade would be inherently different than a Messer blade. Both are single edged and sharp (no, katana aren't sharper). Also, niku has little to do with differential heat treatment, more with blade geometry and intended target. The heat treat only plays in as a secondary factor.

Well, no doubt a blunt blade makes gripping easier ;) Many rondel disarming techniques rely on that. But I wouldn't assume blade gripping can only be done with blunts (too many sources with def. sharp blades show them) and if you can do it with a sharp messer, you can do it with a sharp katana. If and when it makes sense from a martial stand point is a different question.

If I recall correctly, using one hand on the blade while the other on the handle is called "half-swording" is it not?
Gripping a sharp blade in and of itself isn't too dangerous, just so long as you don't slide your hand around.
Most cases though I've heard of half-swording, they used gauntlets or some form of hand protection.

Afaik halfswording was a fighting style against opponents in plate armor with thrust orientated swords that were not sooo sharp in the middle of the blade, where to grip them.
From a messer I would expect more sharpness there.

The problem is that we have lots of gripping the blade in treatises that do NOT contain armored combat. Such as Messer. And I see no evidence to suggest they used blunts (in one or all of the manuals). In fact, single-edged blades make gripping much safer, there's only one edge you need to worry about not touching. 

pgandy : you can sharpen your blades any way you want of course but again, there is no shred of evidence to suggest sword were only sharpened in the top half. On the contrary, the originals we have tend to be sharp all the way down (certain exception exist, as usual) and we also have techniques like Hände Drücken in the treatises that employ the strong of the blade and being sharp there greatly aids the technique. So as far as we know, swords (and daggers if they are edged, not all were, see rondels) should be sharpened all the way down. Everything else is fantasy. Now, the edge geometry can differ substantially from foible to forte, with a stronger/steeper angle further down (which does make it just slightly less likely to cut you) but it is still sharp in the sense that both bevels meet and the edge easily slices paper. 

I used the word "flat" somewhere? I don't think someone with a formal training needs to be explained the difference between "cutting edge" and "flat". Any technique with any sharp sword that goes for half-swording involves the flat. Someone above was talking about holding it by the edge, protected or keeping it still. 

I'd seen it in the dvd with blunts, gripping carelessly around the "edge".
I thought that would be only ok for demonstrating some disarming techniques.

You could solve all your problems with cut resistant gloves. No edge can cut through my gloves. Even a literal razor can't cut through them