Have a scan over who has won the NRL premiership over the past two decades or so and one combination keeps poking its head up.
The relationship and skills of the No.9 and No.7 are often the canary in the coal mine telling fans if their team has the goods to raise the Norm Provan-Arthur Summons trophy above their heads.
Speaking of the coal-rich area of the Hunter Valley, the Danny Buderus-Andrew Johns connection worked a treat in 2001.
In Canberra, the Steve Walters-Ricky Stuart partnership did a fair job in 1989, 1990 and 1994.
And then there's the collective "aaaaah" for what Steve Edge and Peter Sterling mustered between 1981-83; Kerrod Walters and Allan Langer for the Broncos in 1992-93; and the sixth senses of Cameron Smith and Cooper Cronk from 2006 through to 2017 – seven grand finals together among that lot.
Cronk said after his time with Smith drew to a close at the Storm: "One thing I will say about Cameron Smith is that every single pass he sent me was perfect – just out in front of me, right on my chest – every single time."
Smith: Feeling fresh and looking forward to next year
And they both knew what they'd be doing with that pass every single time.
Cronk established a similar kind of rapport – maybe not to the exact depths – with Jake Friend at the Roosters.
The hooker and halfback touch the ball the most. If they are as sharply in sync mentally as they are physically then magnificent things happen.
Interviewing Danny Buderus ahead of the 2006 Anzac Day Test, which would be his last with Andrew Johns in the Kangaroos jumper, and said with a smile and wink: "Behind every good halfback is an even better hooker."
The telepathy between your hooker and halfback is gold.
Even representative halfbacks rarely can do the magic all on their own – think Johnathan Thurston the year after Aaron Payne retired, Daly Cherry-Evans after Matt Ballin left, or Mitchell Pearce once he broke his partnership with Friend and moved to the Knights.
They need time to reconnect with a new No.9. And if the hooker keeps changing then the canary's feathers are seriously ruffled.
So the No.9-No.7 combos emerging for the 2020 season could cause a few birdies to spring into song across NRL clubs.
What can Pearce do with a talented, young hooker like Jayden Brailey, who already has 69 NRL games and three finals campaigns to his name?
Or how unfettered will Nathan Cleary feel with international No.9 and premiership-winner Api Koroisau by his side?
And stepping into Brailey's shoes at the Sharks is his brother Blayke to partner the ever-ready, ever-steady Chad Townsend. Blayke has already played in two Canterbury Cup grand finals in addition to his 15 NRL games in his maiden season last year.
Townsend scores from his own second tackle kick
Real excitement is bubbling beneath the surface at Brisbane with childhood teammates Jake Turpin and Brodie Croft reuniting at Red Hill – and the same goes with the Raiders for British buddies Josh Hodgson and George Williams.
The wild card is Sam Verrills and Kyle Flanagan at the Roosters, who barely have 20 NRL games between them.
You get the sense they will start to accelerate in the way Reed Mahoney and Mitchell Moses did at the Eels in 2019.
So let's settle back and see what this 'marriage' of the most important two ball distributors in our game can create over the coming season.