That matches the interval between their 1989 and ' />
Back so soon? It's only been four years - and one new album - since U2 last played in Auckland.
That matches the interval between their 1989 and 1993 visits. Back then, between the earthy, earnest Lovetown tour - one of the biggest this country has ever seen - and the extravagant Zoo TV shows, the band not only reinvented itself musically but reconfigured how bands of their stature played stadiums.
Tonight, 40,000 of us get to see if they've done that again.
Last year's No Line On The Horizon album (as bassist Adam Clayton tells Scott Kara here), is possibly the last in a back-to-basics trio which started with 2000's All That You Can't Leave Behind and 2004's How To Dismantle An Atomic Bomb.
It's also achieved a fraction of the sales of U2's other noughties albums, possibly due to a lack of any definitive hits.
But it's easy to imagine Horizon tracks like the stomping Get On Your Boots causing the same sort of excitement down front that earlier-generation noisy anthems did.
And the ballad Moment Of Surrender should have the cellphone-as-cigarette-lighter-waving brigade out in force.
So this time U2 have something to prove. But they also have a very big platform to do that from.
All the visual evidence suggests that the "Claw" stage of this 360° tour is a great leap forward from the 2006 shows, which didn't exactly lack for spectacle or whiz-bang production.
Of course, U2 and New Zealand go back a long way. Local fans were early adopters of their early albums. Then there was One Tree Hill, the song written after the 1986 death of Greg Carroll, their Kiwi stage manager.
Clayton says Auckland - and New Zealand - are still special for U2 to visit.
"The connection with Greg, and the affinity with Greg and our history with your country is strong. As well as that I think it's that kind of special bond that two island cultures have with each other. In the early years, when we were spending a lot of time touring America and Europe, when we came down to the Southern Hemisphere there was something very reassuring about landing in New Zealand. We always have fun here, we get on with the people very well - and the crowds are fantastic."
Scott Kara talks to U2's Adam Clayton
U2 in NZ: A Short History
U2 Fans: They Will Follow