@JavelinJoe Plus are they really saying a sword blade could be grabbed by the whip and not have the whip be cut it to shreds?
If you knew anything about how whips are actually constructed and how swords work, this wouldn't surprise you. Most functional whips are made of rawhide (
not rope), a material that's honestly a pain in the ass to cut at the best of times (when properly treated), that is then braided to further increase its strength; the Zulu, in particular, used rawhide to make large, lightweight shields for war and they were quite effective against the weapons the Zulu expected to fight.
And as for swords, especially straight swords, it doesn't matter how sharp the edge is, if it's stationary, it's not cutting anything; a plain edge only exacerbates this. Cutting regular rope with a plain edge is pretty easy, if you have a bit of momentum behind the sword and the rope is completely stationary (see those ridiculous Cold Steel demo videos), but with the sword tangled and the holder of the "rope" struggling to keep you from moving it? Yeah, it's not cutting a damn thing.
The better question is, if she
must use a flexible weapon, why a whip and not something even sturdier, like a long flail? Hell, since she's shown to be perfectly fine whipping out a dagger, why not a kusarigama that combines the two? Granted, it's a fairly uniquely Japanese weapon, but since that dagger was literally a tanto in shirasaya, I don't think that's a problem for this series.