"As long as I can remember I always wanted to be an All Black," he recalled.
"I remember at 6 playing my first game for the Cargill Bears school team in Tokoroa. Dad put up posts on the lawn and I used to do the haka with orange peel in my mouth."
Barry Wilson didn't actually coach the nipper Kahui, but the Tokoroa club man remembers him standing out among his contemporaries in those days of the early 1990s.
"I remember Richard playing club rugby for the juniors in the morning and you could never give the guy enough rugby," Wilson said.
"He'd finish his game and look around for other teams to play for, even if they were a grade higher. Richard would always hang around looking for the chance for another game."
Wilson also recalls having the feeling, even back then, that Kahui was one who could make it.
"You always knew he was one of those guys that would go a long way. He just had the right head for it."
Kahui's first All Black memory was in 1997 when New Zealand played England at Old Trafford.
The All Blacks won 25-8 - and England's players did a lap of the ground applauding the crowd. No wonder that stuck in a young mind.
A word association game would link "Kahui" with "injury". Indeed a man with lesser resolve might have given up on his dream.
The trimmed version reads: 2007, leading up to his first Super rugby campaign, he blew a shoulder; after making his All Black debut the following year - one the player remembers as "a great year" - he busted it in the Super rugby final of 2009 against the Bulls, which led to another six months out; and in 2010, after playing a full season with the Chiefs, a shoulder went bung in the first Tri-Nations game.
One shoulder has been badly damaged twice, the other once. Kahui has had his down times, wondering: Why me? But as for jacking the whole business in? Never.
"I certainly never wanted to leave the game, or stop doing what it takes to get back.
"There has been the odd morning when I'd wake up and think, 'Do I really have to go and do the same rehab drills I'm doing every morning?'
"You get days like that, but football is my dream. I'm passionate about what I love doing.
"When I'm told I'm not good enough any more that's probably when I'll give it up."
Kahui's game is built around strength: powerful running allied to rugged defence. Did he consider tempering his defensive style in the light of the injuries, shoulders being rather important when it comes to tackling?
"Only one of them came from tackling. It was bad luck really. The rest came in awkward situations and I think anyone who hasn't had a bad shoulder would have done the same sort of thing.
"I'm never going to start thinking about tackling softer. It's something I like doing. but I'd probably take a bit more care in between weekends to make sure I'm doing all the rehab."
Kahui's versatility has meant five of his 12 test appearances have been on the wing. He acknowledged that skill had helped him at times in selections. Like tonight, against Tonga.
"I feel really comfy there. At the moment I see myself as a winger.
"My preference is still No13, but I've been given an opportunity to start in a World Cup at home, and I'm really thankful.
"Wing, centre or prop, I'm just happy to get out there."
It is ample testimony to how the selectors, Graham Henry, Wayne Smith and Steve Hansen rate Kahui that it took just one game back against South Africa in Port Elizabeth last month to convince them he had a role to play in the cup campaign.
He scored what might be termed a typical Kahui try that day, from 25m holding off challenges and forcing his way to the tryline in a couple of tackles.
Kahui admitted he lacks the speed of a genuine wide quick man, such as a Doug Howlett, or current teammates Zac Guildford, Israel Dagg or Corey Jane.
But he feels he can compensate with other skills, such as his work under the high ball and, as he said, "I'll chase kicks until the 81st minute".
"At centre it's more up in your face, whereas on the wing you're covering kicks and trying to mark space.
"Centre is more about physicality and strong ball carries and defence. It's not as physical on the wing, but you've certainly got a lot more running."
Running won't worry Kahui who, despite his protestations to the contrary, would not be human had he not endured the occasional doubt that, given his history, he'd make it.
"Looking over the last 12 months, it has been a bit of a ride. I never doubted I could get back, but it's very fulfilling."
