Warren Gatland has set the scene for the All Blacks' visit with an inflammatory reference in his Lions book.

It's just one paragraph in a book full of them, but with his thinly veiled threat that he had the power to reveal "explosive" details about the All Blacks, Warren Gatland has lit the fuse on what could be an incendiary final week of this tour.

Welcome to the All Blacks v Wales, version 2017. More to the point, welcome to one more round of Warren Gatland v Steve Hansen.

Strap in for the ride because this will almost certainly be fun. And maybe just a little wild.

For those with short memories, the last time these two Kiwi coaching heavyweights went toe to toe, we had a series for the ages back in June and July, with Hansen's All Blacks finishing deadlocked 1-1 with Gatland's British and Irish Lions.

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There was controversy, claim and counter-claim, and that was just the pre-tour press conference. And alongside the two finest rugby teams on the planet playing themselves to an impasse, we had the two most voluble coaches not named Eddie Jones imprinting their personalities all over the series.

It was fabulous rugby. And brilliant theatre.

It was the best of times, and if you believe Gatland's book, In the Line of Fire: The Inside Story from the Lions Head Coach, it was also the worst of times.

But it is one paragraph in particular from that tome that will not have escaped the attention of those involved with the All Blacks who will hit Cardiff on Sunday (Monday NZT) surely now as motivated as they can be to put the exclamation point on their 2017 season.

Here's what Gatland writes in his book: "I have heard of some things about the All Blacks that could be quite explosive if they were made public, and if it does get dirty then I will raise a couple of those things. At the moment I'm just keeping my counsel."

Now that is some statement, on the record, in print, in his own book.

It is difficult to think of it as anything other than a threat, and it will be interesting what the All Blacks brains trust makes of it behind closed doors. At this stage they are not willing to respond in the public arena.

All Blacks coach Steve Hansen was asked in Edinburgh what he made of Gatland's claim, and he told Stuff he had no comment to make. New Zealand Rugby chief executive Steve Tew offered an identical response.

But they will both be fuming. For Gatland to hint at "explosive" revelations, but provide no detail, is questionable. Remember, this is from a coach who complained vociferously about the treatment he received from certain segments of the Kiwi media during the Lions tour.

Gatland also wrote that in New Zealand "it's the first time I've felt there's been an orchestrated campaign to unsettle me, and to split the squad".

That reference was right above a paragraph in which he wrote about a New Zealand rugby reporter having intimate knowledge of Hansen's squad that you couldn't obtain "unless you're talking directly to someone in the All Blacks set-up".

It all establishes a tantalising backdrop to this final week of the All Blacks' November tour.

The All Blacks are 5-0 under Steve Hansen against Wales (all on Gatland's watch), having beaten them 46-6, 36-22 and 39-21 in New Zealand in June last year, 34-16 in November 2014 in Cardiff and 33-10 in November of 2012 also at the Millennium Stadium.

Gatland's record, since taking charge of Wales in 2008, against New Zealand is 0-10, with five defeats at home, and five away.

In fact his record with Wales against the three southern hemisphere superpowers does not bear scrutiny. As well as his 0-10 mark against New Zealand, he is 1-13 v Australia and 2-10 v the Springboks.

All of which is sure to have him on edge this week in Cardiff as he surveys another chance to break his duck as Wales coach against the All Blacks.

Maybe he saw something in the Lions series he can exploit. He certainly managed, with the rush defence and the surprising capacity to attack with ball in hand at key moments, to unsettle the world champions in their mid-year matchup.

But does he have the horses to do something similar with Wales?

It sets the scene beautifully for the final week of this tour, where the All Blacks will be desperate to avoid one of those final game banana skins that are so difficult to avoid in your final outing of a long and gruelling year.

But Hansen has plotted furiously over the last few months to avoid just that pitfall. He has spelled key men at every opportunity. He has rejigged travel schedules to ease the load on his heaviest carriers.

It is all about finishing this year strongly. Now it is very much all about sitting Wales on their backsides.