What kind of fucking idiot would use a katana to do perpendicular blocks of a giant 2 handed sword? At least it shattered eventually, like anyone with 1/2 a brain would know it would if used like that.
Maybe if he's going to use a unique weapon that other people in the academy don't, learn how to use it first and don't try to use it like it's a western longsword like a blithering idiot?
Like others have already said, no way would harder and more brittle steel used in Katana's hold up to that kind of abuse, it should have shattered on the first block. It's sharper, sure, but much more fragile.