My two (Canadian) cents:
First and foremost - any country that doesn't recognize a citizen's right to bear arms is likely to have a pretty bad track record when it comes to the use of force (deadly or not) in self-defense. As a Canadian, I have a legal right under the Criminal Code to use deadly force to defend myself
- but since I know what public perception is with regards to that issue, the first call I made would be 911, and the second would be my lawyer. And until he arrived and I had a nice chat with him, I wouldn't be saying one word
to police, other than "Lawyer."
On katanas (that's "samurai", by the way
) - absolutely not in a home defense scenario. Any blade that length is simply too long to be wielded effectively in the confines of a home. An enclosed hallway with a low roof essentially limits you to a stab, rather than a slash. Even the shorter swords (gladius, machete) will still be a less than optimal choice. If you have to use a knife, use something with a six-inch fixed blade - a "hunting knife" to use a common term. This does reduce your range significantly - but with all of the non-firearm home defense weapons, you're not going to be able to "stand your ground" and let them come to you - the element of surprise is crucial.
A short, stout blunt object, like a steel baton or wooden bat, is another option. Not that someone who gets stabbed is going to instinctively fight back, but the business end of a good baton will put stars in someone's eyes for a moment, hopefully enough for a second swing. Repeat as necessary.
In all cases, however - "no gun" is a home defense scenario I wouldn't want to be in, outside of a Home Alone