Watch the video of the greatest try ever scored in rugby. Gareth Edwards touched down for the Barbarians against the All Blacks in 1973 at Cardiff Arms Park - but he wouldn't have scored under rugby's new tackle rules.
It is a thing of rare beauty, from Phil Bennett's magical, almost-backwards sidestepping, the support play, No 8 Tommy David's one-handed bullet pass, lobbed on by Derek Quinnell to Edwards whose acceleration outstripped the cover defence.
That try wouldn't exist today. All Black wing Bryan (BG) Williams booted the ball deep into Barbarians territory; Bennett retrieved it and peeled off his sidestep, leaving discarded All Blacks everywhere. He passed to Wales and Lions fullback JPR Williams - who is tackled head-high by a desperate BG Williams (but manages to get the ball away).
Fast forward 44 years - imagine the game being reffed by Wayne Barnes. Does he play advantage 20m out from the Barbarians line? Does he, hell. Out comes the red card and one of the finest games of rugby ever played would be ruined. Certainly, it would be at least a penalty and the game stopped and altered forever.
I'm not just being beastly to Barnes (it wasn't a forward pass, after all ...). Any ref faced with the new high tackle laws would have halted play. They will be problematical and we can expect more criticism from players and spectators about how they (a) make rugby into some politically correct parody of itself and (b) transfer concussions from ball-carriers to tacklers.
Denied the opportunity to aim at the chest of the ball-carrier (to dislodge the ball; denied because of the risk of the tackle sliding up and being ruled illegal), tacklers must now aim lower.
In one of the first matches under the new rules (Saracens v Exeter), four concussions came from tacklers' heads meeting bony hips and knees. Exeter coach Rob Baxter pointed out: "In a year's time, with the pressure to push towards low tackles, if we end up having more concussions than we have currently with the change of tackle emphasis, what will be the next decision?"
Even worse, the latest professional survey on concussion in British rugby revealed the number of concussions has risen for the fifth year in a row - but only 20 per cent were suffered by the ball carrier, 47 per cent by the tackler.
So in our headlong rush for safety, we just might have hung the wrong man.
Here's a prediction: if the laws stay, there will initially be a rush of scoring by teams even as defence coaches everywhere begin teaching their charges to tackle as effectively as league players. Quite simply, they are still better at tackling, particularly head-on.
I can remember training with my local club rugby team, watching as the leaguies (who shared a pitch with us) also trained. They practised tackling on tractor tyres rolled down a considerable slope at them; they had to stop them dead. They did. We practised going to the bar.
Some British journalists are waxing lyrical about the new laws bringing more attacking rugby (translation: less tackling and ball-killing); it must be said anything which restores the ability of our northern cousins to attack like they could in 1973 is to be applauded and has to be good for the global game. Offloads will promote big scorelines like 44-42 but defences will re-assert themselves as the tackling improves.
Another prediction: there will be further modifications to the breakdown. Last year's experiment with no hands in the ruck was a failure but the concept was sound - trying to restore the lost art of rucking, hoping players arriving en masse would steamroll over the ball to win possession. Player safety was another consideration, reducing the big collisions in the clean-out, the only part of the game a hallowed rugby rule (thou shalt not tackle a man without the ball) is ignored.
The changes failed because rucking didn't really happen. Most teams didn't contest the breakdown or did so minimally; they preferred to fan out across the field and use defensive pressure - double-teaming and chest-high tackles to prevent offloads - to stimulate mistakes. It looked like rugby league. The ball-fetching openside flanker disappeared from view; they would be extinct under those rules.
But if we can find a way to encourage rucking, lose the clean-outs and their injury-promoting qualities and ensure forwards are engaged in a battle for possession rather than strung out across the field delivering high tackles - then we might be on to something.