Cairo has 40 cards. He said it was the lowest number you could have and one of his goals while in Brisbane is to add to that number. "It's good to have more, but not too many."
He said it was a complicated game and his mother, Shirley Williams, agreed.
She said she was proud of her son for winning and hoped he did well in Australia.
When asked who he would take along with him across the ditch, Cairo said: "It was always Russell."
His uncle Russell Tangiwai had spent some time playing with his nephew, developing skills for competitions.
Cairo said his favourite part of the game was the counting and adding of points.
His grandfather, Nicholas Pataka, said the game had helped his grandson "in so many ways".
"Numeracy and literacy has improved and his ability to communicate with others has improved because of this."
He is sponsored by Yu-Gi-Oh! Singles and Tu Meke tattoos and are looking for more to help promote the region when he plays in Brisbane. If Cairo wins in Brisbane then he could go on to compete in the United States.
His grandfather said everyone was "very excited". "We are hoping to promote and inspire other children and family to play and enjoy what Yu-Gi-Oh! can give to a person and whanau."
James White, founder of Hobby Co, who is the official New Zealand representative for Konami, the makers of Yu-Gi-Oh!, said they had run the national championship every year since 2005.
Mr White said it helped with numeracy, literacy, and was a "fantastic way to be part of a community, forging friendships and building confidence".
"Playing similar games during my teenage years is what kept me from failing of the rails, when so many of the people around me were."
