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In an in-depth interview with Newstalk ZB's Elliott Smith, Hansen gave his take on how World Rugby can act in response to several studies that have concluded concussions suffered during a player's career can have lifelong repercussions, including early-onset dementia and chronic traumatic encephalopathy.
Rugby union has one of the highest rates of concussion among team sports and many former players and coaches have been calling for radical changes to the rulebook to reduce their occurrence.
One recent suggestion came from Lions legends Sir Ian McGeechan, Willie John McBride, Sir Gareth Edwards, Barry John and John Taylor, who wrote a signed letter to World Rugby in early August calling for the sport to ban substitutes. They claimed the measure would increase fatigue in the starting XV, producing less intense and less frequent collisions. The average size of player would be reduced, too, as more of a premium would be placed on fitness and aerobic capacity rather than size and strength.
However, while Hansen believes change must come to the sport, he disagrees with this proposal.
"I don't agree with Ian in this instance, I don't think changing the subs is going to help one iota, I think it actually just compounds the problem because you'd have a lot of fatigued players out there. So for me that's not the issue.
"The issue that we have in our game at the moment is there is no clear officiating of the rules.
"If you look at the rulebook, it talks about a ruck and it never talks about the breakdown. Breakdown is a word used more often than any other word in the game - there's not even a rule for a breakdown and we have an old, antiquated law that says two people will bond over the ball and that'll be a ruck. Well that never happens in the game."
When asked about the recent test series between the British and Irish Lions and the Springboks, Hansen argued that style of rugby was one nobody wants to watch.
"You've got two big packs and two coaches who don't have any faith in what's going to happen if they throw the ball around, so they just beat each other up. 'Let's slow the ball down, let's get off our feet, do whatever we can to make sure our defensive line is stable so we can keep battering'.
"It's not a game that anybody wants to watch. Yes we want a good physical contest, that's what the game is all about – physicality, speed, using the ball and skill. Could you say we saw that in that series? Of course we didn't. And it turned a lot of people off.
"All of a sudden, the All Blacks became popular again - 'let's hope the All Blacks can save rugby'. It's not about the All Blacks saving rugby, it's about everyone that's involved in it taking some ownership and saying 'right, we need to do something here'."
Hansen suggests a simplified and clearly-officiated breakdown would increase the pace of the game; meaning there would be fewer players in any given defensive line and therefore a reduced amount of physicality in the tackle and fewer head knocks.
"A lot of the injuries we're getting are actually friendly fire, so you and I make the tackle and I knock my head against your elbow or your head.
"So we'd create a game where there's a clear picture at the breakdown that yes, ball is quicker, the defensive lines won't be able to set as quick; so attacking lines will be attacking against destabilised defences more often and there'll be more space.
"I think the opportunity to be really brutal will dissipate."
Hansen says this particular issue is a symptom of an even wider problem in the sport: that few people understand how it is actually played.
"I think the biggest issue is it's too complicated. When players don't understand it, when people watching the game don't understand it, when coaches don't understand it, when referees can't be consistent, we've got an issue and we've got to address that issue."
The way Hansen believes World Rugby needs to approach that problem is by instilling simplicity into the rulebook, so referees can manage a safe and entertaining game.
"What we've tended to do over the years is add, add, add; when history will tell you that if you make something simple, by taking things away, then you'll get more consistent at making those decisions.
"I've been beating my head against a brick wall for quite some time to get people to understand that we're over-complicating it."
World Rugby began a trial of five new laws in August, four of them focused on potential player welfare advancements.
After a global one-year trial period, laws that are deemed successful in meeting the objective of increasing safety while enhancing the spectacle will be tabled to determine whether they are adopted into law at World Rugby's May 2022 meeting, one year before the 2023 World Cup in France.