Imagine a combination of rugby, dodgeball, tag and live-action role play involving two games being played at the same time – and it's a game native to New Zealand.

To the uninitiated, it looks pretty complicated.

It's a ball game most Pākehā and even many Māori haven't heard of – kī-o-rahi. Not just any ball game, but one based on a colourful pūrākau (legend) of a man called Rahitutakahina rescuing his wife, Tiarakurapakewai, after overcoming several obstacles involving a taniwha, a lake and an ice bridge.

IAIN MCGREGOR/STUFF Tim Graham throws the ball as his school practices for the upcoming kī-o-rahi tournament.

Some Māori communities have been aware of the game since at least World War II, but the origins are unclear.

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Ara Institute has been holding rounds of kī-o-rahi on Monday nights and now a bunch of eager Christchurch kids are taking it on.

IAIN MCGREGOR/STUFF Yaldhurst School is one of six Christchurch schools learning to play kī-o-rahi.

Yaldhurst Model School, a primary school on the outskirts of Christchurch, is testing out kī-o-rahi with its students. Five other schools are following suit.

Sport Canterbury learnt kī-o-rahi from TOA Sports at Ara Institute and thought it would be a good sport for primary schools to try.

The Yaldhurst student body also thought it was a good idea and, alongside Sport Canterbury, taught the sport to five other schools.

Sport Canterbury community sport advisor Robbie Harlow said the process was quick and pupils were keen to learn to the game.

"We went through the whole game with myself and someone else from Sport Canterbury and they then brought in five other schools to learn in a day.

"They've then taken that back to their schools and practiced and that's resulting in a cluster tournament."

Wednesday's tournament will determine the first Christchurch primary school kī-o-rahi champion.

The children at Yaldhurst insist it is not complicated once you get the hang of it, so here are the rules, according to Rangatira Tu Rangatira (and there are many variations):

Two teams, the kīoma and the taniwha, play on a large circular field. Like basketball it has four quarters and teams rotate at half time.

Kīoma score by touching the pous (pillars) with the kī (ball) then running the kī through Te Roto (the lake) and placing it down in pawero to convert pou touches into points. Like a rugby try.

Taniwha have to hit the tupu in the middle with the kī. Kīoma have kaitiaki (guardians) around the tupu to stop the taniwha from hitting the tupu. In turn the taniwha must stop the kīoma from scoring.