A dull sword replica is dangerous to handle...
A sharp sword replica is very dangerous to handle...
A sharp sword (katana) is very very expensive and dangerous to handle...
Never touch any part of the blade with your finger, for two reasons:
1. The fat on your fingers will make the sword rust and leave marks unleas you clean it of according to propper methods.
2. If it would have been a real sword you would have cut yourself and the blood would have made the steel rust almost immidiately, unleas you clean it of properly.
Even a dull replica is very dangerous to handle because the blade might fall off in the midle of a swing, which I hope I don't need to explain why that would be fatally dangerous. Same goes for a sharp replica and even a real katana unleas you really know what you're doing. Accidents has happend many times, and will unfortunately happen as long as people try to learn this stuff from books, without teachers.
And btw ZenLateralus, trust me the knowledge you would attain from a book regarding handling a sword or any other physical disciplin, are next to nothing. You certainly wouldn't become a master.
Trust me, if you are serious about doing something like sword cutting, aikido or kung fu then there really aren't any alternative than to put time, money and effort into it, by going to a serious school or dojo where this is taught.
/J