Blocking, as the name implies, involves stopping your opponent's incoming blow from reaching its target. If the blocking action is applied to a sensitive part of your opponent's anatomy at the same time, such as a nerve ending, then it also becomes a strike at the same time.
Blocks should be practiced separately at first so that correct form can be learned. Part of learning to block properly is learning to protect your body's centre line as you block and giving attention to the Point of Origin principle. Kenpo combines the blocks into sequences known as a blocking set and it is one of the first sets that every student learns. Different branches of American Kenpo have slightly different blocking sets with either 6, 7, or 8 blocks in the set. Our blocking set has 7 blocks, starting with an upward block, inward block, extended outward block, downward block, outward block, rear elbow (chamber), and finally the downward palm heel.
When practicing your blocking, start and remain in a training horse stance (which is beneficial by itself), and don't rush - correct form generates speed and power with time. The hands are initially in the chambered position and may be open in a sword hand, or closed in a fist (though the fist is required for testing). The chambered position in American Kenpo is the fist, palm up, in the joint of the hip in training horse stance. The blocking surface is the bones of the arm primarily, and the bones of the hand secondarily. While the form used in the blocking set is not the same as the individual blocks described here, you will use the individuals forms in Long Form 1 during the isolations.
The Upward Block
Starting with your right hand, raise your hand up the centre line of your body with your palm toward your face. When the palm reaches your forehead, snap the palm clockwise toward your opponent. The forearm will attain an angle of 45 degrees with the elbow straight in front of the shoulder. The hand should be away from your face, and your forehead so that it can absorb the impact of an overhead blow without being driven back into your body.
For the left hand, it is the same process, but as the left hand ascends, the right hand descends, with the left hand on the outside of the right hand. The right hand follows the same path, but in reverse, back to the chambered position. The descending hand is always on the inside.
The Inward Block
The inward block crosses the centre line of the body from the outside to the inside. Starting with the right hand, raise your hand across your body towards your opponent's right shoulder with the palm facing to the body at an angle of 45 degrees. Maintain that angle as you strike forwards and across your body ending at your opposite shoulder. Do not allow the elbow to creep outward and upward, but keep it tight into the body.
As you start to retract your right hand along its original path, the left hand follows a similar path to the opponent's left shoulder, crossing in behind the right hand, but not making contact. This crossing action protects your centre line as you change hands.
Are you seeing a pattern here? Whenever you block, you are protecting the centre line of your body, where your vital organs are located (heart, lungs, solar plexus, etc.).
The Outward Block (Extended and Not Extended)
In the outward block, the hand starts on the opposite side of the body, and returns to the same side of the body. For example, the right hand first travels across the waist to the left hip (with the palm down). To perform the block, the right forearm rotates up to the right shoulder. For an extended block, the palm remains rotated facing away from your body, and slightly forward. For the regular outward block, the palm is facing towards the body, and tight into the shoulder.
The difference is in the anatomy of the forearm. There are two bones in the forearm, the radius and ulna, and when the elbow is bent and the hand facing towards the body, the radius and ulna are parallel to each other. When the palm is facing away, the radius and ulna are crossed over each other, making the forearm more rigid.
The motion of the left hand is the same, moving first to the right hip, and then rotating counterclockwise to the left shoulder, but the left hand crosses behind the right forearm.
The Downward Block
In the downward block, the right hand is raised to the left shoulder. When it arrives, the palm is turned towards your centre line. The right hand rotates down toward the right leg, palm down, so that the right forearm points toward the right knee. The left hand is then raised to the right shoulder and as the right hand is retracted to the chambered position, the left hand scrapes down the right arm and ends pointed at the left knee above the left leg. The primary use of this block is to block kicks (usually accompanied in practical usage with a step up the circle, an action designed to get your body out of the way of the incoming strike)
The Chambered Position
The chamber is used to deliver a rear elbow to an opponent standing in close proximity behind you. You can get a bit more power in the chamber by raising the hand from the hip toward the arm pit, and tightening the arm. But for the set, the hand, in American Kenpo, rests on in joint of the same side hip.
The Smothering Palm Heel
From the chambered position, push the right hand to just in front of your belt, palm down, and fingers opened. The finger tips must be up as much as you can manage as the striking surface is the heel of the open palm. As you retract the right hand, the left palm assumes the same position. There is no crossing of the hands in this block. The primary use of this block is to smother knee strikes or uppercut punches.
Sempai Kira Trombley demonstrates the proper way to do Blocking Set 1.