The killer karate chop

Published on September 6th, 2011
The killer karate chop

You’ve seen the movie The Karate Kid, right? (If not, go watch it now…we’ll wait!) In any martial arts movie, you’ll see experts smashing through towers of bricks or tiles using just the edges of their hands. This kind of demolition attack is called tamashiwara, and here’s how it works…

Studies have shown that a karate chop can deliver an impact force equivalent to half a ton in weight (flash fact: weight is a measure of force, specifically the force of gravity on an object, which depends on its mass). All this force, focused on the edge of the hand, is more than enough to break tiles, bricks or bone.

The secret lies in delivering as much kinetic energy as possible to the target, deforming the material beyond its limit of flexibility and causing it to break. To accomplish this, the hand must be moving as fast as possible when it hits the target, so no slowing down before contact, as much as your brain tells you to.

Karate experts practice their chops to finish a few centimetres below the point of contact, with their hand reaching maximum speed around 6m/s just at the point where the unfortunate tile or brick is located. So when they’re faced with the real thing, they’re used to the motion and are able to override their natural instincts against it.

It’s also important to have the bricks supported at their edges, allowing them to flex and break. And, of course – and this is important – do NOT try this at home. Seriously. It probably wouldn’t go down well.