This is why you do not block with the edge of a sword.

When teaching kendo, one important thing about which to remind students is that it's bad to block with the blade of a sword, because it gets damaged very easily. It's better to block with the flat of the blade. This picture (of my wakizashi, after I've clearly messed up a few times) illustrates why.
It also illustrates one of the flaws with movie swordfights: this is what is necessary to produce sparks when swords clash. The sparks are the steel being heated rapidly due to the pressure of a sharp blade hitting a sharp blade. Trust me, if swords in movies actually were real, there wouldn't be any of these ancestral blades being passed down generation after generation. They might be useful as a saw or a steak knife or a file, but definitely not as anything meant to have a continuous, non-serrated edge like a sword.