Having said that I also hold to thae principle of no blocking and insist that the student learns how to meet rather than block which from the outside may look like blocking but when one knows the difference is a world apart.
Niall, your explanations are clear as usual.
Regards all and any I didn't respond to. G.
We have movements in Saotome Sensei's kumitachi that in the basic form would be considered "blocks" although if done well they really establish a stickiness to the blades and receive the energy of the cut rather than oppose it. But since very few folks understand it that way, I'll call them "blocks". At the heart of it though, I was taught that there are no blocks, in weapons or empty hand and that what looks like a block is really a cut or strike.
So, for instance, the aforementioned "watershed" block isn't a block or deflection at all but is really a cut. Rather than move off the line and do the move, one enters and the blade is actually under the attacker's arms rather than under his sword. This causes him to break his posture and momentum allowing him to be cut.
Even movements that look like deflections eventually change as ones sense of timing changes and blades that used to touch no longer due so. Deflections morph in to "slipping" movements which are far harder to counter.
Essentially, in the end, anything that puts your attention on the other guys blade is wrong. If you are blocking or even deflecting, you aren't cutting him. The movements only become blocks if you were late in your cut.