Have you heard the one about the farmer and the assistant school principal?

That's not to say they're dry or boring, they just tend to often come down on the more serious side of the scale, with their own stripped-down sense of humour. Maybe it has something to do with their geographic isolation - two islands that are not really close to anywhere but themselves. Maybe it has to do with a lot more than that.

Either way, if you were to ask Kiwis if they've heard the one about the farmer and the assistant school principal, the last thing they're going to expect is a punchline. And they'd be right not to. For the one about the farmer and the vice principal is no joke. In a country that takes rugby more seriously than anything else, it's a damn serious matter. Many see the farmer and the vice principal in a straight shoot-out to become the next in line for the most important job in their homeland - All Blacks head coach.

Vern Cotter is the farmer, Joe Schmidt the vice principal. While they've both long since left those callings behind for altogether different ones on the other side of the world, they are roots that are never far from the surface. They form a life and style lineage that goes a long way to explaining why these two find themselves where they now find themselves - holding the key to the fortunes of Celtic rivals Scotland and Ireland at the dawn of a pivotally important Six Nations Championship in the year a Rugby World Cup will come to these shores.

But it was the along the Pacific shoreline breaks of Papamoa Beach, in the Bay of Plenty region of New Zeland's North Island, that this remarkable rugby couple first began to make waves. It's about 25 kilometres, give or take, a half-hour drive, from the fertile fields and farmlands of Te Puke to the front gates of Tauranga Boys College, a secondary school that has produced well over a dozen All Blacks. If Joe Schmidt was to leave his office and Vern Cotter was to leave his fields and the pair met half-way, it would have been somewhere along the picturesque, little slice of perfection that is Papamoa Beach. And that fits.

From the get-go Cotter and Schmidt made for a perfect pairing. The first signal of just how well the farmer and vice principal clicked came not far from the golden sands when they brought the Ranfurly Shield back to Baypark Stadium in 2004. It was the first time in Bay of Plenty's history that they had claimed the most historic and storied prize in New Zealand club rugby, the coaching tandem masterminding an unceremonious sacking of the citadel of Auckland at Eden Park.

Bigger things beckoned for Cotter and Schmidt and after going their separate ways to cut their teeth in the professional game with respective support roles with the Crusaders and Blues, they were reunited on the Massif-Central in 2007. Clermont Auvergne may be cut apart from France's heartland in the south but it was the perfect place for the pair to get back to business.

"It was apparent pretty much immediately that they got each other," explains Neil McIlroy, Clermont's team manager, a Scot who was at the heart of the Cotter-Schmidt axis there. "They'd obviously had previous partnerships before I saw it up close. You did get this impression very quickly that they were two very different brains, two very different characters who are very very complimentary to one another.

"They definitely have the drive that Kiwis have. They're obviously coming at rugby and life from very different aspects. You have Vern as the farmer with that agricultural background and then Joe with his teaching background, that analytical side. Yet the passion is the same.

"There's just something about the New Zealand rugby man, what they look for, what they strive to become. They have a nose for the game. It's a certain something down there...there's one thing that's always going to be in common and that's rugby."

Cotter, who had an eight-year stint as a player in some of the more distant French outposts, had already been in the position as Clermont head coach for a year before summoning for Schmidt to join him as assistant, focusing on the backs. He did so after defeat in the Top14 final.

"Vern had been there for a year previously and he had, not so much laid the groundwork, but he had come in on a brief and had shaken things up," explains McIlroy, the former Borders prop. "So when Joe came in it was maybe that bit more settled. Vern is already established and had established a regime and so that would have made the transition that bit easier for Joe. What we do have here in France is the most bonkers domestic competition in the game. If you're coming from a Super 15 background into that you're going to struggle but Joe didn't have that challenge. And then they were able to adapt and grow together from there with European rugby."

The next two seasons were to see the heartbreak repeated with two more final failures that cut both men - and Clermont - deep. For the most fervent fans in the French game, three defeats in a row in the decider seemed too much to bear. But in 2010 Cotter and Schmidt accomplished their mission and mercifully delivered Clermont's first Bouclier de Brennus.

Schmidt departed for Dublin soon after to take on a first head coaching post with Leinster. He was pretty good at it, winning two Heineken Cups in his first two years, meeting Clermont three times in the process, including an epic semi-final triumph over Cotter's crew in Bordeaux in 2012. But Cotter, the elder of the pair by four years, levelled the scores the following season by dumping Leinster out at the pool stage in 2013. Schmidt departed for international rugby taking up the Ireland job, and proved pretty good at that too, winning last season's Six Nations in his first go.

After a longer lead-in than many would have liked, Cotter is now firmly in place as Scotland coach and his early results, five wins in seven and a near-miss against an All Blacks side who were, admittedly very weakened, have created a wave of positivity. The Six Nations beckons and the boys from Bay of Plenty are back in close proximity. Great friends and better foes, there was some nice verbal jousting at last week's tournament launch when Cotter insisted "Joe's a much better coach than me" and Schmidt responded that he "wouldn't want to physically lock horns with him...he's a big, strong man". The phoney war will be much more real in mid-Match when Ireland come to Murrayfield with potential for a lot to be on the line on the Championship's last weekend.

It shouldn't be lost, however, how different things may have been. Cotter was a strong and in lots of circles supported candidate for the Ireland job in 2013 before the IRFU chose their man. However McIlroy, for one, thinks things panned out better for all parties.

"I think Vern is exactly what Scotland needed," he says. "They needed a simpler game plan. They needed a kick up the backside too if I'm being honest. After quite a bit of upheaval, they needed a strong-willed coach who what you get is what you see. I think both [Joe and Vern] went to the right teams at just the right time. If you talk about that farmer and [teacher] comparison, Scotland were maybe in a place where they needed the farmer [more]."

It was Captain Cook who came up with name Bay of Plenty when he pitched up on those beaches in the 1770s and found an area with an abundance of riches and resources. As Cotter and Schmidt, the Bay boys who became master rugby navigators, get their resources in order for the coming battle, it is us observers who are likely to reap the riches.

Heard the one about the farmer and the vice principal? Don't worry, the next instalment is on its way.