Canada is a crazy place for knives. The government there doesn't trust their subjects with much blade.
There's a code you have to use to send them into Canada....people have posted it here before but I can't remember what it is---something like "camping gear" or "collectible recreational item...". And even if you do that, if customs grabs it randomly you're cooked.
This is my understanding anyway. Maybe a Canadian can better inform you or correct me if I'm wrong.
Yep, wrong.

You can put "knife" or "sword" on the package, and Customs doesn't care.
I have mailed knives to the USA with "Knife" or "pocket knife" listed as the contents...no issues.
However, UPS and Fed Ex in Canada flat out refused to ship knives to the USA, despite the fact that True North Knives ships exclusively by UPS (I guess UPS must figure they sell spoons...).
It's a Postal or courier issue, not a Customs or country issue.
As long as it isn't specifically prohibited item (push dagger, switchblade, balisong or "knuckle knife) and it cannot be flicked, it'll cross the border just fine. :thumbup:
As for the Postal and courier services, they are always the annoying linkage in the whole procedure.