of course they do, people vary greatly in size
Well, I don't vary in size at all, by my bastards have.

Anyways, it sounded like he was under the impression that bastard swords were mostly heavy. Not so.
Part of the confusion may be because the term 'bastard sword' has been used over the past century to mean different things. Some have used it to mean the same as 'longsword' (a sword that is not necessarily heavy either), but that definition seems to have become a lot less common in recent times, at least in the 20 years since I've been in the WMA community. After all, we have the term 'longsword' for that, and the German longsword tradition is pretty well-recognized these days, so we might as well use 'bastard' to mean something else, I guess. That's the rationale I keep hearing. So a lot of modern practitioners/swordmakers simply use the term 'bastard sword' to mean a sword that isn't quite a longsword but isn't quite a single-hander either... it's usually somewhere in between.
Personally, I find the latter definition to be the most useful, and apparently Master Trim finds it useful too, as I've had at least half a dozen bastards he's made that are quite maneuverable and quick. Some were truly 'hand-and-a-half' swords, while others were more-or-less the size of longswords, but lighter and easier to use in one hand. And then of course the Hanwei/Tinker bastards are insanely fast...
