It's a fighting discipline studied every day by thousands of young actors and actresses hoping to star in anything from King Lear to Rocky.

Plenty of ``stage blood'' has been spilled in the Parade Theatre at Kensington's National Institute of Dramatic Art facility, the site of many a beating made in the name of art.

But Camden trainer Alicia Smith says the blood will be genuine when the venue hosts the Australian open full-contact championships for Kyokushin karate.

``People are knocked out clean cold. They get broken sternums, jaws, noses and all that stuff,'' she said.

``It's internationally recognised as the toughest form of karate.''

Smith operates Young Tigers Dojo, a karate training gym at Smeaton Grange that will supply its best fighters to the July 27 championships.

Some have been with the dojo for years, having studied the art as part of a journey of self-discipline.

``You've got to be mentally strong and you've got to want to do it,'' she said. ``You'll always find that where three students start two will quit.''

It's a physically brutal sport but Kyokushin doesn't start that way for beginners.

Like ballet, children learn the basic movements of the discipline before having the chance to implement them in a one-on-one battle.

Children won't miss out on upcoming titles because a separate July 26 event will cater exclusively for non-contact fighters.

``It's very hard to explain. The kids are too young to hit,'' Smith said.

``It's similar to full contact but the kids actually pull their techniques.''

If you've ever heard the term ``pulling punches'', this is where it originated.

``They've got to get within three centimetres,'' Smith said.

``There are four judges with clickers on the corners of the arena, when they think the fighter has got a good technique they use the clickers.''

Young Tigers fighters aren't allowed to participate in contact fighting until they are 16, at which point they go into a ``colts'' division with an armoury of protective gear including helmets.

Senior fighters shun protection and often face blows to the head.

Two of the Tigers' finest will fight at Kensington and some 15 juniors will suit up for the non-contact battle.

All enjoy the sport but for a variety of reasons. ``For some people they do use it as a social thing, some people do it just to go through their grades,'' she said.

``Others just love their fighting and they want to fight,'' Smith said.