The so called downward X block you refer to has many practical applications. I saw the one in the clip you posted. Abernathy is well respected. but I have found some of his bunkai to be just not applications I would do. I have a problem with a few of them being just to complicated to be practical. but he does have some very good ones too. That said I must also say that every technique, posture, stance, body shift, hand position, ...etc. has multiple different ways it can be applied. The low X block is a technique that I have one application that I'll share. That is a joint lock into a throw. Rather than make this overly complicated I will not give the entry. Lest just say that as things progress you find yourself with the attackers wrist and you have him behind you. you have his right arm over your right shoulder with his arm turned so that the palm is facing up. By putting downward pressure on his wrist you lock /bar his arm creating pain that causes him to go up on his tip toes trying to release the pain. but you don;t try to restrain him in this position it is only a fraction of a second in the middle of applying the throw. by dropping to one knee and at the same time bringing his wrist down you cause the attacker to be throw over your shoulder. This is worse than just a regular shoulder throw. The attacker has absolutely no options once the throw starts. He comes over you landing close in front of you. He can end up landing on his head, or shoulder. He could easily break his neck or dislocate his shoulder. Depending on how you lock/bar his arm you could have done damage to his elbow as well. This is not a technique that I would actually do in practice. When I or my students have tried nasty things happened to the Uke even though no one was intentionally trying to hurt anyone. Note: for those of you that either don't like Kata, or Don't understand it, this technique is in Pinian Godan (Heian or Pinan number 5). It appears in the version I do as a jump landing on one knee while doing what looks like a low X block. Many people are taught that you are dropping to one knee and blocking a front kick attack. Sorry but that is just stupid. Anyone that would do such a thing deserves what he gets. It is not a block for a kick. It certainly is not you dropping down in front of an attacker to block his kick. And besides why would you use two hands to block or deflect when one hand can do it??? Any time both hands are involved something that requires both hands is happening.
On another note: in Kata many different types of strikes and what appear to be blocks happen. What is not understood is that when one hand is forward and the other closer to you as in one hand striking while the other is pulling back, both hands are involved in the actual application. There is what many people call the "two hand rule". that states that no matter what appears to be happening both hands are used to make the technique work most effectively.
I really wish you would post an email address so you can be contacted. In several of your recent questions I have asked you to contact me at my regular email address. I have not heard from you and do not know if you are reading my answers.....
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its in pinan/heian godan jion, chinto/gangaku, and several others.
the problem is you are thinking in absolutes as well as thinking its a block, it can be a number of thinks including a collar choke, joint locks, strike, etc.
the word uke does not mean block it means to receive
I like Abernethy myself. I've seen this video, and I agree it's complicated. But it isn't something I would toss, just something I need to work on.
That said, don't always assume that techniques have to be done standing. In an X-block, you could be leaning over an opponent on the ground; an x-block over the neck as you tighten the strangle as you grip the clothing over the shoulders can be effective. Conversely, you can do the same if you were on your back with your opponent on top of you. These are just two of a myriad of techniques that could be interpolated from the form.
http://iainabernethy.co.uk/content/pinan-heian-yodan-bunkai-gedan-juji-uke-strangle-video
Though this was interesting.
I've heard the Gedan juji uke can be used as a jointlock, but don't see how. The main thing we use it for in my style is a knife disarm.
What the heck is the point of the cross high block/jodan juji uke? Now that I think about it it isn't in any of the kata's/pinons I've learned. It might be in one I haven't.
http://www.google.com/imgres?imgurl=http%3A%2F%2Fwww.shotokenshukai.it%2FUserFiles%2FImage%2FTecnica%2FParate%2Fjuji%252520uke.jpg&imgrefurl=http%3A%2F%2Fwww.shotokenshukai.it%2Fpage.asp%3FSEZ%3DDisciplina%26SOT%3DKhion%26NOT%3D234&h=293&w=422&tbnid=IWQPJphDqMsfyM%3A&zoom=1&docid=GKgghHOdcpk4KM&ei=0oxuU4_LL8n5oATaoIDIDA&tbm=isch&ved=0CGQQMygSMBI&iact=rc&uact=3&dur=607&page=1&start=0&ndsp=20
