Waka Nathan doesn't just answer the door, he fills it.
This, you can't help but think, is how you want all your sporting heroes to look like when they're 75 - upright and tall, Nathan has an undeniable presence and looks in great health.
On the outside, at least.
Nathan invites us into his apartment at the Bruce McLaren retirement village in East Auckland, where the apartment blocks reflect the auto-racing industry, with names like Hulme, Amon and, in Nathan's case, Monaco.
Nathan folds himself into the couch and tells a story of his bone-carving pendant. It is a story, his family admit, that might have shifted over time, but it doesn't really matter - it is a connection between father and son.
"I was playing a training game at Waikaraka Park," says the Otahuhu club and Auckland stalwart. "And my father [Sam] comes over at halftime and asks if he can make a presentation to his son. He handed me this and said it was a badge of courage. I wear it every day. It goes everywhere with me."
You want to talk about courage? Great. Listen in.
Courage is playing without fear in the loosies for Auckland and the All Blacks in an era when hard men ruled.
Courage is defying snapped Achilles tendons and broken jaws to be so good the French give you a nickname that might not have got past the gatekeepers of today - le Panthere Noir, or the Black Panther.
Courage is defying your in-laws and racial stereotypes to marry the love of your life (and 51 years of marriage, three daughters and seven grandchildren later, who won that argument?).
Most of all, courage is sitting on your couch, in the above-mentioned retirement facility, telling the country you have Alzheimer's disease.
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Nathan is not alone. On the day the Herald launched this series which investigates the links between head injuries suffered in rugby and dementia conditions including Alzheimer's, his wife Janis took him to the village library where they read the story about the Taranaki Ranfurly Shield team of 1964, and the plight of five players who have died with, or are suffering from, dementia.
It struck an immediate chord.
"I played with Wolfey and Ross Brown. Wonderful little players. Wonderful men," he says.
A heartbreaking condition
Nathan was a key part of coach Fred Allen's unbeaten All Black teams of the late-60s and was a bashed-up tourist on the 1967 tour to Canada, the UK and France, where they were hit by a foot-and-mouth outbreak - which prevented them going to Ireland - and from winning a grand slam.
Like that Taranaki team, there's more than one player on that team now suffering from debilitating dementia conditions.
Tony Steel had an eye for the finishing line. A national champion sprinter in the mid-60s, he used that speed to his advantage on the wing for the All Blacks, scoring 20 tries in 23 matches, including seven tries in nine tests.
He was a finisher; the greyhound at the end of the line. If you gave a wing a bit of space on the outside, you expected them to score tries and Steel was better at dotting down than most.
After an Achilles tendon ended his career in 1968, Steel's teaching career took off and he would end up as headmaster of Hamilton Boys' High School from 1980 to 1990.
He wasn't finished with public life, however. In 1990 he became the National MP for Hamilton East, was voted out in 1993 and re-elected to parliament in 1996, where he remained until 2002.
Not long after leaving politics, says wife Raewyn, he began a different sort of battle.
"Tony has had frontal lobe dementia for the past 10 years," she says from Hamilton. "He has been in a private dementia home for the past four years.
"I kept him at home for as long as I could but was no longer able to provide the fundamental care he needed."
Raewyn feels a lot of things about her husband's condition, but mainly it is anger.
"It is heartbreaking. It is terribly, terribly sad. In 2002 he was still an MP, he had his sporting achievements, he was the headmaster of a big, prestigious school and still it didn't make a difference."
Raewyn was not married to Steel during his rugby career, so cannot speak for the injuries he might have endured, though her husband's description of one incident remains vivid.
"He did have some head injuries. There was one terrible injury that broke his cheekbone and the doctor had to put a spoon up inside his mouth to push the bone back out," she says.
That would have been the violent collision with Otago flanker Warren Townsend while playing for Canterbury.
Reading the reports from the day is instructive: Steel, who underwent surgery to repair the bone in Burwood hospital, had just one concern - that he would be ready to fly out with the 1967 All Black tourists.
Hard as a bag of spanners
If Nathan was the divinely skilled forward and Steel was the flying wing, then Graham Williams was something else altogether.
As hard as a bag of spanners, Williams had an almost maniacal appetite for possession.
"The way he played, you'd think his nose was glued to the ball," says veteran rugby correspondent Wynne Gray.
"He'd get bashed around all the time and he'd keep getting up."
At what cost?
Sharon Williams, Graham's wife, said her husband was struck down by frontal lobe dementia five years ago.
Frontal lobe or frontotemporal dementia affects the the areas associated with personality, behaviour and language. It tends to hit sufferers earlier than Alzheimer's, typically between the age of 40 and 75.
Williams is 71.
A year ago, the former openside flanker was also diagnosed with motor neurone disease, another illness caused by brain dysfunction.
"There is no way of knowing whether one would have happened without the other," Sharon says.
In one of those curious coincidences, it was only a broken jaw suffered by Nathan on that '67 tour that allowed Williams to gain his first test cap.
He played all four tests on the trip and played his fifth and final test in Brisbane in 1968, which also happened to be Wolfe and Steel's last tours as All Blacks.
Despite playing well for Wellington for a number of subsequent seasons - he played a record 174 matches and was an icon of the province - Williams was never picked for the national side again.
Sharon Williams says her husband took numerous head knocks over the course of his career and it is impossible not to consider whether this has played a part in his health struggles.
"As far as Graham is concerned, it has been a very gradual decline," she says.
A sparkle in his eye
The inexorable progress of Alzheimer's disease is often measured in three stages. Nathan is at stage two, or the moderate stage.
Moderate Alzheimer's can last for years and is typified by the patient confusing words, getting frustrated or angry, and forgetting events and their personal history.
He first started showing signs of decline after the 2011 World Cup. Daughters Alana and Janine said they assumed the missing "sparkle in the eye" was just the result of tiredness after what had been a busy schedule during the tournament.
"He was such a social person," Janine continues.
"Whenever there was an event or something was happening, dad would always say, 'I'm a starter'. All of a sudden he'd start to say, 'I'll give it a miss'."
Displaced vertebrae weren't helping the cause either. Within months, Nathan had transformed from the life of the World Cup party to man who couldn't sign his own name and was in and out of Middlemore hospital.
Surgery to correct the spine alleviated pressure off the base of his head and physically Nathan returned to regal form, but the sad truth is his brain will never experience a similar recovery.
As a family they've talked about the rugby, talked about the hits - Nathan once played with his jaw wired up after having it broken on the last day of 1963 by Llanelli's Terry Price (who he posed happily for photos with afterwards) - and have reached the sort of murky conclusions most would before realising it wasn't the important thing.
Ensuring a quality of life for their husband and father was more pressing than searching for the reasons why.
Nathan himself is almost blasé about the hits he took. This was the age when admitting pain was seen as a sign of weakness.
"I looked at guys like Colin Meads and Stan Meads. If they were hurt they just carried on playing, so I just thought I should too," Nathan says.
Really, it's only when the subject of his favourite rugby player comes up that Nathan gets animated about the physical price of the game.
McFarlane Herewini was an ethereal presence in an age of power. His ability to ghost down the skinniest of blinds, dummying and shimmying his way into and out of trouble made him must-see at the height of his powers.
That sparkle in Nathan's eyes that went missing a while back is back in full force when he talks about the five-eighth.
"He was a champion little footballer. No two ways about that. I loved watching him play. The way he would step and dummy. Just wonderful."
Herewini's impish style saw him run into traffic jams on the odd occasion, but as he told his son Mac Jnr, he didn't often put himself in a situation where he got "caught".
"In those days the game was tough," Herewini Jnr says.
Herewini was on the tour to Britain in '63 but wasn't quite the same force he had been in previous years and a 3-3 draw with East Wales at Cardiff was to be the last time he pulled on the black jersey.
Herewini died in 2014, aged 74, after a series of strokes.
"He had dementia for at least five years before he died," his son said.
"We saw the changes in his personality. He was always a positive person and had purpose in his life but that [the dementia] created a change.
"His behaviour became quite negative."
It would be stretching things to say a little bit of Waka died when his great mate died, but the light certainly dimmed.
"It hit him very hard," says Janine.
"They had a lot of fun together growing up in Otahuhu. In dad's words, Mackie was a 'cheeky little bugger'."
In its own way, the news that another mate, Neil Wolfe, was struggling with dementia also hit him hard, but it lit a fire under him and his family.
So that's why we're here sitting in his apartment, talking to a great man who is proving that Alzheimer's can't strip away your courage.