TOKYO, 18 Oct - New Zealand have not won the past two World Cups by accident. They have done so by constantly evolving, staying ahead of the game and being the best at solving problems.

And it appears they are finding clever fixes again in 2019, although the problem on this occasion was one any team would love to have.

New Zealand's issue was they had Richie Mo'unga and Beauden Barrett. Both are superb fly-halves and both offered slightly different benefits to the team. But which one should get the No.10 jersey?

The All Black response was simple, find one of them another shirt and put them both in the team. Mo’unga, above right, took 10 and Barrett, above left, grabbed the full-back jersey.

They are not the first team to tinker with the traditional blueprint for building a backline, which generally looks like this. 

10. Creative and a good kicker in attack – defensively sound
12. A crash ball wizard who can get you over the gain line – a defensive rock
13. Quick enough to exploit the overlaps your inside backs create – defence is less important
15. Can deal with high balls and counter-attack loose kicks – tackles anything that comes through

Increasingly, teams have been seeking different combinations to improve defence and attack.

Why does your inside-centre need to be a one-dimensional ball carrier? What is stopping you from having two 10s in your team? Why does your 10 need to be good at tackling? Just move him somewhere else and put a better tackler there when you are defending.

Australia used to move Bernard Foley to the front of a lineout and put hooker Stephen Moore at 10 when they were defending lineouts. Teams can be creative with how they set up.

England have done so in the recent past, and also at RWC 2019, with Owen Farrell starting at 12 and George Ford inside him, giving them the dual playmaking option - with a third kicking option, Elliot Daly, behind them at full-back.

But perhaps no one has been as successful as New Zealand in creating the environment in which their two gifted playmakers can flourish.

A perfect example of how the Mo’unga-Barrett axis operates is the George Bridge try against South Africa. Mo’unga is the initial creator with his perfectly placed crossfield kick. Once Ardie Savea is brought down, New Zealand realign in their attacking shape towards the near side of the field. The blitz defence of Pieter-Steph du Toit splits the pitch in half. Mo’unga cannot do too much once he is ‘trapped’ in the densely populated far side of the pitch. Barrett has more space though. He has three options; carry, pass, or kick to Dane Coles on the wing. The benefit of having a second fly-half on the pitch is that he can identify all these options and choose the right one.

When a fly-half is tackled or involved in a breakdown it can be easy for a team to lose their structure. The fly-half dictates what the players outside of him should do. When he is not there those players can revert to just carrying and ignoring the outside options.

New Zealand do not have that issue. If Mo'unga is out of action, as he was in the clip below, Barrett can step in and provide structure. Barrett and Mo'unga pair up to move New Zealand into the ideal attacking position – directly in the middle of the pitch. Mo'unga is out of the game at the bottom of the breakdown but Barrett spots space ahead. He is not the only player who would spot this opportunity but he might be the most skilful at delivering the kick.

Against Scotland, Ireland showed they could stop Finn Russell with their relentless line speed. The logic was simple, remove the key creative force by giving him no time on the ball and you starve the rest of the team.

That logic does not quite work when your opposition has two creators. Do you blitz one and give the other time? Blitz both and risk burning all your matches before the end of the game? Or, blitz none and come up with a different plan?

Those are the questions Ireland's defence coach Andy Farrell will have been wrestling with this week.

RNS sl/sdg/icr/bo