Downward-fist block
Gedan-barai uke (literally: “low-level sweeping block”), the downward-fist block is used to literally sweep aide punches and kicks to the abdomen.
Downward-fist blocks are chambered by bringing the blocking hand up to the opposite-side ear, with the palm facing inward. Hold the opposite-side hand open over the exposed floating ribs on the blocking side, as in the picture below.
[front-view photo of gedan barai chamber]
Pull the blocking arm's elbow down diagonally as far as possible, then thrust the fist straight downward. Do not lock the elbow -- instead, keep it slightly bent to perform the Unbendable Arm technique. The opposite-side hand pulls across the abdomen into a chambered position, setting up a counterattack.
This must be practiced slowly until it becomes one fluid motion, which is gradually sped up. Slow is smooth; smooth is fast. It is tempting just swing your arm in a large downward arc, but there's no power behind such a block; it would be like using spaghetti noodles to smack attacks aside.
[video of a swinging gedan barai, from the side, failing hard]
Do not cross your arms in an X-shape across your chest. If you do this, an opponent can push on the outside arm, and trap them both against your chest.
[front-view photos of improper gedan barai, and trapping the arms. ]
Only use downward fist blocks to protect the abdomen. Attacks below the waistline are too low for downward-fist blocks, unless you lean forward, and compromise your stability. Also, leaning involves an unnecessary additional energy expenditure to right yourself. Instead, use knee blocks to deflect attacks to your legs or groin. A leaning downward-fist block makes your undefended head easier to reach and abuse.
[side-view photo of leaning as a result of blocking too low, and being pulled off-balance ]
