I would say that it is not so much a block as a move that transitions immediately into kam na. It can be (relatively) safe if you apply the right footwork and body shifting. I didn't listen to the audio in the above example and don't know what I missed but in our school we primarily train it with the left hand on top.
Can you guess why?
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"Look, I'm only doing me job. I have to show you how to defend yourself against fresh fruit."
For it breeds great perfection, if the practise be harder then the use. Sir Francis Bacon
the world has a surplus of self centered sh1twh0res, so anyone who extends compassion to a stranger with sincerity is alright in my book. also people who fondle road kill. those guys is ok too. GunnedDownAtrocity