I found this video last night while looking for Jow Ga Kung Fu and I was surprised to see that the movements were very similar to some of the grappling defenses and strikes found in Jow Ga Kung Fu. It was close enough to make me think that TKD blocks are really not blocks. I gave it some good thought. These so call blocks also don't make sense when I'm thinking about blocking a TKD kick. Low block - This is the same movement that is made in Jow Ga Kung Fu to "wipe a grabbing hand." basically someone is trying to grab your arm or wrist for control and you are striking the grabbing hand. In Jow Ga we use an open hand instead of the closes fist. The reason I don't think this is a block is because of the position of the block as he does it. The concept is that you strike the grabbing hand with the fist and pull your arm back during the strike to escape the grab attempt. Middle Block - Is a good ole fashion hammer fist strike. If someone grabs your arm you pull them towards you which gives you an opportunity to either to strike the grabbing arm off your arm. It looks like it could be a hammer fist strike to the head The High Block - looks very similar to an anti-grabbing technique that scrapes the grabbing arm from the bottom. If someone grabs your hand from the top then your bottom hand goes under your arm and you scrape along your arm to strike the forearm of the grabbing and upward. The reason the hand travels under the arm is because it's less interference and you need to send the force upward. To test the concept have someone try to grab your arm and right before they are able to lock the grab, strike their forearm upward. It's the same principle as the "Low Block" one hand strikes as the other hand escapes. Outside block - This looks like Chin-Na to me. Someone grabs your arm so you circle it in order to force their wrist to take a bad position. The pop at the end allows you to escape the grab and puts your hand in position to counter grab. The other arm that comes to your chest is actually the position for a loaded punch ready to go. Basically you escape the grip, control the arm and now you are in position to counter punch. I COULD BE WRONG, BUT I DON'T THINK I AM lol. Some of you TKD guys try this out and let me know how it works and if it works.