During my apprenticeship, I was told by Ronan O’Gara to think three or four phases ahead after any set piece attack. Playing international rugby nowadays is the PhD to that undergraduate level of attacking sophistication and there is no better place to take such a course of study than Carton House.

Just how Joe Schmidt combines Johnny Sexton, Bundee Aki, Joey Carbery and Robbie Henshaw on Saturday should provide a glimpse of Ireland’s future path because how we play now is how we intend to succeed later.

I expect to see them all on the pitch at the same time, at some stage, against the troubled Springboks.

Ireland need all four of them. I heard Schmidt’s joke last week about the new breed of centre, saying how Henshaw is his smallest midfielder now he’s recalled Stuart McCloskey and promoted Chris Farrell.

Both men should be used this month. I’m guessing the Fiji game. I also presume Garry Ringrose comes straight back into the team against France in February. Ringrose isn’t so big, he’s certainly not a collision hungry player – granted, he’s growing all the time – but the evasive centre is more important than ever.

Defensive structures are researched and rehearsed to block any light from pouring through. The opportunity comes in mismatches – big against small, fast against slow – and having finishers to convert them

The game has clearly changed, grown more fierce. When I started playing professional rugby the best chance of a try was off set piece without a single ruck.

Admittedly, that was a long time ago. The game evolved into launching players at iron-clad defences in search of slight system failures or individual weakness, to create line breaks off second or third phase.

Depending on execution that would or wouldn’t result in points.

Now, it’s more complex. The defensive structures are researched and rehearsed to block any light from pouring through. The opportunity comes in mismatches – big against small, fast against slow – and having finishers to convert them.

The space still exists, it’s just harder to find.

The game has changed drastically in the two years since I retired.

Take Andrew Trimble’s try in Paris when Ireland won the 2014 Six Nations.

One ruck to suck in midfield defenders, a Conor Murray show and go and Trimby comes off his wing to side over untouched.

Detail in motion, looks easy, but break down each moving part. The Irish scrum – I’m giving Mike Ross credit for wheeling Thomas Domingo and the French pack towards the touchline. Andrew knows to drift inside and pick a direct line of running. Murray to Sexton who puts Brian O’Driscoll crashing up the middle (not before a hint of a dummy pass to his bearded sidekick who plays a career defining role fixing Gaël Fickou and Mathieu Bastareaud).

Sexton, followed by Heaslip and Chris Henry, clears the ruck in two seconds flat. France come around the corner to face the Clongowes Three – me and the Kearneys – but Murray has already returned from whence he came.

Still look and sound easy? That attack requires 15 fully focused brains, all of whom have practised it over and over at training. Every detail or obstacle is planned for. Say, French fullback Bruce Dulin was wise to this well-worn Schmidt ploy – see Cian Healy’s try against Clermont in 2012 when O’Driscoll carried into midfield off a lineout before a reverse pass has Rob sprinting over the gainline – Henry, Heaslip and Paul O’Connell are shoulder dips away from Ireland needing a second ruck before Peter O’Mahony falls over the line.

That was then (Schmidt has literally made a career from tearing open French sides). Defence has narrowed the advantage over offence again. We saw this at the dawn of professionalism when every serious union team had a flat-nosed Rugby League defence coach.

Rugby, entering 2018, looks to be about structured spontaneity. The opportunities are still there, they are just harder to find. The key is to put creative players in positions to unpick structured defences.

Saturday’s starting XV will be fascinating as it gives the players, the public and our rivals a glimpse into Schmidt’s thinking and the route he intends to take towards Japan 2019.

Aki should be a central figure. The Connacht hero gives Ireland a midfield option we have not had since Kevin Maggs and Rob Henderson.

Aki also brings an additional creative spark. He is far from poetry in motion – alá Matt Giteau or even Isa Nacewa at 12 for Leinster this season – but his ability to play ball on the gainline (holding numerous defenders in the process) gives Schmidt’s Ireland a new dimension.

Centre as an art form begins with defence. Not just big tackles, but spatial awareness. The hardest lesson to learn is the difference between defending and tackling

It’s his ability to destructively win collisions, more often than not, before freeing his hands. Keith Earls and Jacob Stockdale can benefit the most. I hope to see Irish wingers set free. There will be frustration, hands in the air knowing the chance is gone, but the timing will come.

Bundee, Carbery and Henshaw can fill a much needed second wave of creativity, punching or making holes when Sexton is shut down or rucking or doing what he shouldn’t be doing because he needs to lead by example.

Adding that new element in attack seems important if this group are to surpass their potential. If we are to go where no Ireland team has ever been before: a World Cup semi-final.

Defences, starting Saturday against South Africa, have become significantly harder to unlock. The Boks finally got their act together in the one point loss to New Zealand on October 7th.

I remember, in one of my early columns, picking Jesse Kriel apart after they lost to Japan at the 2015 World Cup.

Centre as an art form begins with defence. Not just big tackles, but spatial awareness. The hardest lesson to learn is the difference between defending and tackling.

Kriel was exposed for both Japanese tries. He was 21, it was his fifth cap, but he was clearly a fullback/winger wearing 13. Now he has 25 caps and has become an impressive physical specimen, as is Damien de Allende, but Schmidt will see familiar flaws. The bait will be set for Kriel and others to commit when they should sit and hover, to tackle not defend when Ireland attack.

Ireland, and our flood of returning Lions, should beat South Africa

The difference between then and now is line breaks don’t guarantee tries. Amidst all this change, one constant remains. The All Blacks.

They seek space over contact. When they seek contact it is with the intention of creating space.

That should be a core philosophy of any rugby side.

The Springboks almost atoned for the 57-0 defeat to New Zealand in Cape Town last month with a return to their most cherished value.

Physicality. It wasn’t enough to beat the world champions. It was a highly emotive performance that seems unlikely to be replicated on a cold November evening in Dublin.

Ireland, and our flood of returning Lions, should beat South Africa.

We know the improvements that will follow when Rassie Erasmus takes over from Allister Coetzee next year. Munster’s run to the Champions Cup semi-final and Pro14 final look even more impressive on viewing their form this season.

One of the biggest calls for Schmidt will be fullback. Simon Zebo has opted for France but the way the game has gone players like him are needed to beat defenders. It does make you wonder how big a priority he was to keep. He may not have started out as a Schmidt player but he has grown and thrived under Joe’s influence. Suddenly a test match that suits Zebo is upon us and he is gone.

Saturday feels like day one of the 2019 World Cup campaign.

There will be something new in the way Ireland approach the November Test series. The attack must evolve. Picking both Carbery and Aki would be a serious statement of what Ireland know they need to do; play unstructured rugby, identify the opportunity after a truck load of punishing phase play and having the nimbleness to slip through ever decreasing gaps.

It is becoming increasingly hard to be an attacking force in rugby.

Appropriate numbers need to be committed to rucks that occur far enough apart to stretch the opposition. All the while Sexton needs to be directing matters and identifying where the next point of contact or decoy runner will be launched. An extra set of creative eyes can only benefit Ireland.

But whenever Schmidt goes back to him Henshaw has delivered. Chicago a year ago being the most recent example.

So, to four key Irish men. Find the space – born off Aki or Henshaw busting contact – before Sexton or Carbery, or both, throw the pass.

It used to be criminal not to score a try after travelling 10 metres over the gainline. Now that only tends to offer the opportunity to repeat the process, over and over again, until the defensive shell cracks. Then it comes down to the player’s ability to deliver the scoring blow, perfectly timed, at the point of exhaustion.

That’s what makes the Springboks an ideal opponent first up. Passing through rapidly closing gaps – in the Brendan Venter-anchored defence – comes with a heavy toll.