Tony Ward: Simply the best - Consistent performances mark Conor Murray as the greatest to ever wear 9 for Ireland
Taking the 1948 Grand Slam as a starting point, there have been many great Irish scrum-halves down through the years.
From Ernie Strathdee, John O'Meara and Andy Mulligan through to Roger Young, John Moloney, John Robbie, Colin Patterson, Robbie McGrath and Michael Bradley, the green No 9 has been in good hands.
And all that prior to professionalism.
In more recent times Peter Stringer, Tomás O'Leary, Eoin Reddan and Conor Murray have been but some of the outstanding exponents of the base-of-the-scrum art.
Naturally each had their individual strengths; Stringer's bullet-like passing off either wrist, Patterson's irrepressible sniping, Bradley's 'third-wing-forward' defending, and Moloney's tactical astuteness, for example.
I was privileged to play alongside five of the above and while each was exceptional in their own right, I believe our greatest scrum-half will be playing in the Aviva this afternoon.
I first watched Conor Murray play AIL for Garryowen against Blackrock in Stradbrook in 2009.
I had been tipped off by my moles in Dooradoyle, so seeing this ex-Munchin's youngster perform (he was also the Limerick club's goal kicker at the time) to the level he did came as no surprise.
I knew I had seen a future international in the making but I wanted to reserve judgment because of the Light Blue hype.
The Munster call followed in 2010 and within two years of that Stradbrook appearance he had been called up as a 'bolter' to Declan Kidney's 2011 World Cup squad.
He may have been but an eaglet at the time, but by the end of that tournament he was first-choice scrum-half. This eagle had landed.
And there he has stayed, adding Lions tours to Australia and New Zealand in 2013 and 2017, coming on in two of the three Tests in Oz before starting all three in the drawn series last summer.
From a No 10's perspective, first and foremost the scrum-half must be an excellent passer.
It's hard to believe but prior to the greatest of them all, Gareth Edwards, the torpedo or spin pass was an alien concept between nine and 10.
"You throw, I'll catch," were Barry John's immortal words to his half-back partner in the early days at representative level but as the most complete rugby player developed the art of spinning and diving in the one movement, the King was crowned alongside.
That fraction of a second gained through speed of delivery made for the telling incision by JPR (Williams) and the try-scoring pass to Gerald (Davies) at full tilt.
The pass is the fundamental principle upon which any scrum-half is judged. But add the ability to snipe when the moment is right, plus the art of kicking consistently, and an out-half's lot is a happy one.
Keep the opposition back-row honest and it's a very happy bunny wearing 10.
But Murray is even more than that again. He is another Bradley when it comes to covering and tackling alongside Peter O'Mahony, Dan Leavy and CJ Stander.
Piece all that together and here is the consummate scrum-half.
But there is another facet to the Limerick man's game and this is the one thing that puts him on a pedestal above every other that went before.
I am in awe of his on-field temperament.
He never gets fazed. He has all the relevant skills but it is that ability to keep the head when so many others are losing theirs that really sets him apart.
I'm not sure he's even aware of it but put yourself in any rival player's boots, specifically back-row and scrum-half, and try and imagine just how irritating, indeed psychologically deflating, it must be when this particular cage, and in such a pivotal sector, is beyond rattling.
I was fortunate in that I was blessed with a big-match temperament.
The bigger the game, irrespective of nerves, the more I enjoyed it and I would like to think the better I played.
But I, like most of my contemporaries, was still vulnerable to being got at.
Maybe it was because we didn't have the protection (cameras at every angle) that players have today but revenge was often in the air pretty soon after.
I was in no position to practise the law of the jungle as it applied in rugby back then and far be it for me to pretend otherwise, but I could dish out the verbals.
The only problem was, and I even realised it at the time, my cage was being successfully rattled.
So when I watch Murray in action now what I see is the perfect role model, and not just as a scrum-half but as a player.
One thing you know is that when he doesn't get back up immediately from contact, be it a tackle or whatever, it's time to worry. He's tough as nails but uber cool to boot.
From a coach's perspective he can turn his hand to anything or to borrow from Clint Eastwood, play it 'every which way but loose'.
New Zealand No 9 Aaron Smith is a hugely-talented and equally-influential scrum-half but in terms of totality and 'go to' factor at this point in time Murray is the best there is.
Of course he and Johnny Sexton will be targeted today but so too will Greig Laidlaw and Finn Russell.
That is the way of the game since it was first invented, even before Webb Ellis picked up the ball and ran.
The defeat in Murrayfield last year was a shock to the system but to suggest it has a relevance to today's outcome is for the birds.
The dressing-room feeling in the aftermath of that game is what Joe Schmidt and Rory Best will tap into, and there it ends.
There was a time too when the Scots were king of the ruck in the northern hemisphere.
Changes in the laws have hampered that tartan whirlwind at the breakdown.
That said, Nigel Owens is a firm believer in opening up the contest at the tackle area and certainly against the English - with skipper John Barclay outstanding over the ball - the Scots' high-tempo intention benefited. Having already spoken about his potential performance, the visitors today will hope that today's man in the middle, Wayne Barnes, will allow the same latitude.
For differing reasons this is a huge game for both Celtic countries. The Scots need to break that away-from-home hoodoo (Rome apart) while for us (and I'm not losing the run of myself here), the Grand Slam is even more important than the Championship.
Opportunities like this come along maybe once in a generation and for this Ireland squad, much like the great achievers of '48 and '09, this is their time and their opportunity.
Even allowing for injuries to Robbie Henshaw, Chris Farrell and Sean O'Brien this is a mighty 23.
The head and heart say Ireland.