This season could be the most important in the history of rugby union. We are entering a 12-month period that will define the game’s future, change the view we had of it looking back, and put down the foundations for global domination that will see rugby challenge the biggest spectator sports.

Will Greenwood

The reason for my optimism is the quality of rugby played in the recent Tri Nations tournament. It was breathless stuff – literally. I have never seen rugby played at such pace for such a sustained period of time. Players were moving the ball from all parts of the field, preferring to run rather than kick, daring the defence to stop them if they could. Props were flinging passes that three-quarters would have been proud of, backs were rucking and taking contact.

This was rugby turned on its head and it sent out a message to teams such as England: play static rugby, dither with the ball at the back of a ruck or maul, try to slow things down, and you will be punished. England will have a lot to think about. They have been trying to move to a more liberated, quick game, the second Test v Australia was exceptional but it can now not be the exception.

After this last Tri Nations, they will have little choice but to be even braver in how they play or they will be blown apart. It really will be do-or-die stuff for the team and management, such was the quality of rugby on offer in the Tri Nations.

I was getting text messages from friends, both rugby fans and sometime viewers, who could not believe what they were seeing. They all talked about the spectacle of what was going on. This was a style of rugby that could draw people away from football, from Twenty20 cricket, from anything that sold itself as fast, sexy and exciting. Rugby was suddenly seat-of-your-pants stuff that you didn’t have to be a purist to understand.

The main driver of this shift has been the new rules and interpretations at the breakdown that were introduced at the turn of 2010. It took a while for teams and coaches to come to terms with them but they now have and it has caused a revolution. Simply put, it has given the team with the ball a greater chance of keeping it in contact.

Over the past few years, the defence has been in the ascendancy. Players such as Richie McCaw, George Smith and Heinrich Brussouw have been the match-winners. They waited like muggers to tackle the player with the ball. They hit low with their shoulders, swung themselves round and back on to their feet, got their hands on the ball, and either won a turnover or a penalty when the attacker was judged to have held on for too long. It was legalised robbery, and it was killing the game. So the rules were changed, again, to a chorus of boos and accusations of tinkering for the sake of it.

I forgive the naysayers because no one, myself included, could have imagined just how far-reaching the changes would be. Today, the tackler must roll away, and the player with the ball has longer to play it back. In effect, the rules have neutralised the limpets at the breakdown, and given teams with the guts and lungs to attack a better chance of success.

As a result, everyone has to pass, ruck, maul and move. Bulked-up players are having to strip down every ounce of fat because the game is moving so fast everyone has to keep up. Teams are revising the way they play.

Take the kick-off. For years, the fly-half would look to stick it up high, giving the chasers time to get to it. Today, they are hitting it hard and low for two reasons: first their chasers are quicker than ever; second, it takes the opposition’s catchers and lifters out of the game. Instead of the static aerial ballet, we now have a start that is more like the murder ball I used to play at school. You cannot allow the opposition any kind of ball, they won’t kick it back to you. It whizzes in, gets picked up and the hits start coming.

It is fearsome stuff, not least because the way of the tackling has also shifted. If you want to turn someone over today, then the best way to do it is to hit them front on. You either want to dislodge the ball, or hit someone so hard you knock them backwards. Let them get past your shoulder, get in behind you, and the new rules will mean you are chasing backwards, scrabbling to stop an attack that can keep going until there is either a mistake or a score of one type or another.

Want to know how far this can go? Then how about this – scrums and most definitely line-outs could become side issues of lessening importance. It’s not that the scrums will be depowered, the line-outs ignored, it’s just that if you don’t make a mistake, or kick the ball out, then why have them? The new rules mean you have a very good chance of retaining the ball and scoring.

The game in England is going to have to adapt quickly. Will it mean a shift in power away from the power and defensively strong sides such as Leicester? Will it mean the death of the drift defence and a reliance on the blitz and nothing else? It’s too early to tell, but what is certain is that sides willing to have a go, to run, to chance their arm and bust their lungs, will have much more of an opportunity than before to give a team like the Tigers a black eye.

Bath, for one, are built for this game. Steve Meehan, their coach, has been preparing his team to play like this when the rules didn’t help. Now they could be a step ahead.

In terms of players, watch out, for it’s the snappy scrum-halves such as Ben Youngs who will go into the spaces around the fringes and get behind defences; flankers such as Andy Saull who have pace, are tricky to put down and have soft hands to keep the ball alive; second rows with running legs and basketball moves such as Courtney Lawes.

For the rest, it’s the runners with the speed of thought and an eye for a gap I would pick: Alex Goode might be ready for the transition to Test match rugby. Muscle will come in useful, but it will be less of an imperative. Big lumps will still make an impact, but I would be picking the movers and the shakers instead.

There will be surprises in this club season, new players will emerge and it will be thanks to the latest rules. Luckily, England’s management and players will have a chance to see how far they have come and still have to go in the autumn internationals. This new style game is exciting but it is also very demanding in terms of fitness and no team are able to play at the pace required for 80 minutes. They can get to half-time and seem out on their feet. However, that is going to change, not least because there is a World Cup coming up.

The next year will see some of the hardest fitness training ever, and players will change shape and develop new skills. And while that sounds good, it is not all great news. What I worry about is that the diversity in shape and size that made rugby so special will have to be sacrificed to produce players aho can compete on an international level. The lumpy, slow scrimmaging prop may well disappear, as will the hunt for the 7ft second row, or light but lightning fast three-quarter. In their place will come the robo-player who can do all the physical stuff, sidestep like a winger, and run a sub 10-second 100 metres. The dark arts, the real technical stuff that purists so love, will disappear because the ball will never be in one place long enough for any niggle or cunning to develop. And the gap between the elite and the rest of the rugby playing public will grow even wider.

The Telegraph, London