One of the oddest, and most misunderstood aspects of Taekwondo has to be the chambering of blocks. When looking at this practice, it seems absolutely counterproductive to the purpose of the technique, which is to block an assailants attack. Yet, chambers for our blocks remains unquestioned by most martial arts practitioners and most are completely fine with the movement because, "that's just the way it's always done." However, when sparring or practicing reality-based training, none of these practitioners execute blocks with chambers, they simply block the technique. It would be impossible for anybody to react to an attack and have enough time to both chamber their block, and actually block the attack. So if we never actually chamber our blocks before executing them in a real situation, then why train them that way?
The reason why we all line up in class and execute our blocks with big chambers is simply because that is what our teacher tells us to do. And the reason he tells us to do it is because that is what he was told to do when he was in our spot. And nobody ever seems to have an explanation for chambers other than, "it makes your blocks more powerful." However, this reason is simply wrong.
Chambers for our blocks are done for several reasons. The first reason, which is why we practice chambering blocks in the first place, is due to Okinawan kata. Because the movements in kata were replaced by labeled techniques, each movement was removed from a specific sequence in the kata, and practiced on its own, as a single technique. Although we are only intending to practice what we perceive to be a blocking technique, we are actually practicing multiple techniques that were taken from kata, and are now being practiced completely out of context.
In kata, it is true that many of the techniques generally taught as "blocks" are actually not really blocks. Although there may be a blocking technique of some sort somewhere within the chamber of the block, the movement we believe to be the actual block is most likely not so. When looking specifically at "blocks" in kata, it is important to note turning sequences. At any point within a kata, a turn may be executed for two reasons. One, the turn is used to keep the kata within a small area, or two, the turn is used to show a grappling technique. Using the motions of the "block" along with a turn, one will often begin to discover grappling technique against numerous assaults.
Another thing to note about blocks occurring in forms is the sequences that end in blocks. In the old Taekwondo poomsae palgwe il jang, the first sequence of the form is to turn left executing a low block, then step forward and execute an inward middle block. And then the sequence is repeated to the other side. Now why in the hell would someone block two techniques and then simply turn away? This is because blocks can also be strikes as well. If a sequence in a form ends with a block, try and visualize this technique as an offensive move, because it was most likely intended to be a strike.
Let's now look at blocks not in the context of forms. There are three basic movements when executing a "block." The first movement is the initial chamber, when you are supposedly preparing to execute the block. The second and third movements happen simultaneously, those being the actual blocking technique coming from the chamber, and your other hand pulling to the side of your body at belt level.
Now instead of looking at the technique from this perspective, let's try another. For this example, try and visualize a traditionally executed low block, stepping into front stance, as we have all practiced a gazillion times. However, visualize the hand that chambers high towards your ear as being open and blocking an incoming punch using the chambering movement. The other hand simultaneously comes across your body, preparing to grab your opponents arm right after you executed the block. Now, visualize the actual "blocking" motion from the chamber: The hand that is pulled into your side has now seized your opponents arm and is pulling it in towards your side in order to off balance him. At the same time, you are stepping into your deep front stance in order to have a strong, offensive movement with strong stability and balance. At this time, you are executing the "low block" straight to your opponents groin.
Within this one simple movement which we have been practicing since white belt, contains an entire self defense sequence. This thought process can be utilized for all of your traditional blocks and one would be able to discover a multitude of brutal self defense techniques contained in their "blocks." And as I said earlier, try and study the movements of the blocking techniques as they are performed with turns, such as with our kata/poomsae. If you already have some grappling experience it should be easier to notice similarities in the movements of some blocks to various joint locking and throwing techniques when done with a turn.
These are some basic concepts one should consider in order to discover a deeper meaning of both why blocks are executed with chambers, and what the true applications behind the motions are.