Who ya got? The reliability and consistency of Ryan Crotty; or the power and unpredictability of Ngani Laumape? It might be Steve Hansen's biggest head-scratcher ahead of his World Cup selection cutoff.
The All Blacks World Cup midfield makeup solidified markedly after Hansen's public affirmation last Monday in Auckland that Sonny Bill Williams has "nothing to prove" in terms of his inclusion for Japan. The strong inference was that, if fit, the 33-year-old offloading savant would be part of the 31-strong squad chasing an historic hat-trick of global titles.
The "if fit" part remains a crucial box to tick, with Williams still to retake the field in Super Rugby post-knee surgery. But he's due back possibly this week and from what Hansen said, if his veteran No 12 proves his readiness then he can pack his bag now.
"He's already proved himself. He's played 51 tests. That's a lot of test matches; that's a lot of proving," said Hansen. "What we need to see is him getting back on the track. Then we've got to ask ourselves is his fitness good enough for him to be selected in the team?"
Presuming Williams times his run well, that leaves, at best, three more midfield spots for Japan. Maybe only two if Jordie Barrett is viewed as a capable backup.
Given they usually carry midfield cover on their bench, it's more likely they take four for a tournament of this magnitude.
At centre Crusaders linchpin Jack Goodhue is now considered nigh on an automatic selection and in-form Chief Anton Lienert-Brown has to be close to that also, with his ability to cover both spots and runs on the board as an impact man.
That leaves room, maybe, for one more specialist 12 in the mix, which looks a straight showdown between two outstanding contenders in Crotty and Laumape. Both offer compelling cases for selection and either would be desperately unlucky to miss a spot on the plane for Japan.
But such is New Zealand rugby's strength in this position – consider that Ma'a Nonu, Matt Proctor, Rob Thompson and Braydon Ennor are also hovering – there is every chance a world-class performer gets left at home.
Crotty and Laumape would come into that category. They are both in outstanding form in Super Rugby, have been part of the All Blacks setup in recent years and would add significantly to the makeup of Hansen's history boys in Japan. Where it gets really intriguing is that they are mirror image type players and personalities, with such different strengths that the decision essentially comes down to personal preference.
Former All Blacks coach John Hart says Hansen's faith in Williams is admirable and he compares it to the strong backing he gave to the under-pressure Dan Carter before the 2015 event which was rewarded with a standout tournament by the experienced No 10.
Hart says loyalty to someone who has performed under pressure for you is part of that faith, as is confidence in his ability to front and logic in the part you see him playing.
"They obviously consider Sonny an integral part of their team. He is a bit different to the other options in midfield, and he does have the ability to do a lot more with the ball than the others do.
It's in part recognising that factor."
The coach who guided the All Blacks to their first series victory in South Africa tags a Crotty-Laumape head to head for the final midfield spot a "luxury", but one likely to play out. He considers Goodhue a "shoe-in" for Japan and believes Lienert-Brown must be close to that status after his body of work this year on top of an excellent test resume.
"Crotty has immense experience, immense talent at reading a game and has been a proven leader for them," adds Hart who tips the 30-year-old Crusaders workhorse to get the nod. "It's a balance. Do they go for the leadership, the absolute consistency and know what you'll get every week and add value with a Crotty against a Laumpae who is probably more physical, and more damaging, but doesn't have some of the other growth areas at the moment?
"It will come down to do they want someone to really carry the ball or do they want someone to organise the ball?"
In a World Cup mix it essentially comes down to who slots in best if there's an injury to a starter.
"So if Sonny got injured, which is a possibility, then you'd say Crotty probably delivers more in terms of leadership," adds Hart. "The only concern I'd have over Ryan is his concussion issues. Outside of that I don't see any reason why he wouldn't make it."
Which would be extremely tough on Laumape, Hart acknowledges.
"He really couldn't have done any more. That's one of the luxuries of their selection: they have a guy they know will do the job. But Laumape has a lot of rugby in front him, and this would be no reflection on how they see him going forward."
Of course, the best laid plans can be undone in this brutal sport at any moment. And if injuries struck in midfield, Hart (a board member for the Blues) considers 37-year-old All Black centurion Nonu would be a deserved, and storybook, callup out of his franchise.
"He's been a revelation, playing the way he has, with the commitment and dedication he has. He came back to try win a spot in the World Cup and he couldn't have done any more.
"It will need injuries for him to progress. Laumape would probably go ahead of him because of speed in the legs … but I have nothing but admiration for the way he's come back and applied himself.
"If the All Blacks hit the wall and had injuries in midfield, they'd be very lucky to have a guy like Nonu: passionate, dedicated, and still with the skills and ability. As a backup he would be fantastic."
Ryan Crotty (Crusaders) Age 30 Physical: 1.81m, 96kg Test caps: 44 Strengths: Outstanding tactician, option-taker and tackler. Vocal leader. Consistent and persistent. And loves the big moment.
Ngani Laumape (Hurricanes) Age: 26 Physical: 1.71m, 103kg Test caps: 10 Strengths: Superb ball-carrier, line-breaker and finisher with nose for the line. Improving defender and creator. Low gravity and power make a defender's nightmare.