Re: "blocking" with japanese sword
I'm for edge blocking if you have no other choice. This is strongest part of sword and can really block even strong cut without too much damage. Better to damage a blade then one's own head, isn't it? Flat side will bend or brake very easy and one gets cut/kill.
Redirect fast, strong cut isn't always easy to do, that's why one may practice first hard blocks with bokken and slowly move to redirection. If you can't block strong cut, you can't learn more subtle elements of art like sliding blade on attacker's blade to redirect movementů.etc
The techniques that "knock the other blade down" are numerous, and are excellent to develop right feeling of sword. But it is higher level of art.