Re: "blocking" with japanese sword
Edge vs body blocking:
The theory and practice varies from ryuha to ryuha. Some do edge to edge, some roll the blade from edge to flat, some block flat to edge.
ZKNR seitei iai uses the flat to edge approach in the kata Uke Nagashi (sanbonme), for instance.
One of the things to remember is that the Japanese sword was seldom used in a direct block, but almost always in a sliding or redirecting block (think of aikidome vs a karate-style age uke).