When the Six Nations kicks off this weekend, the easy bit, or easier bit at least, for Lions coach Warren Gatland will be working out which players are going to make his squad for New Zealand.
The hard bit is going to be choosing his captain. Gatland is spoilt for choice to fill his playing ranks. Britain is awash with quality players. It is enjoying something of a golden age and even the untrained eye can see that there are 20-25 players who will already have been pencilled in to make the tour.
Privately, Gatland has said he thinks this will be one of the most talented and best-equipped Lions squads to assemble.
All Blacks coach Steve Hansen wouldn't disagree and the quality on show during the Six Nations will only strengthen that view.
The tournament opener between Scotland and Ireland will give everyone a better sense of just how much firepower the Lions have in their midst. The Scots have had the most meagre representation on the last few Lions tours. They have been the poor relation and their weakness has reflected in the Lions - as the composite side has really only been picking from three and not four nations.
Not now. Scotland will no doubt show at Murrayfield that their representation on this trip should be higher than it has been. Everyone has fullback Stuart Hogg as one of the must haves, but by the end of the Six Nations, centre Huw Davies, prop WP Nel, lock Johnny Gray and perhaps a few other such as Greig Laidlaw, Mark Bennett and Sean Maitland could be in the frame.
So just as Scotland were the flag of weakness in previous years, their new-found strength signifies the depth from which the Lions will be picking their squad in 2017.
But a talented squad won't be enough in itself. As always with the Lions, so much will depend on how well the team comes together. Can they unite behind a fearless captain the way they did in 1997 when Martin Johnson was skipper?
Johnson was the sort of bloke who transcended all national grievances and hang ups. He was a commanding figure who persuaded his peers to care not about historic grievances and to park the politics. The captain of the 2017 team is going to have to be the same sort of non-divisive figure and this is largely what Gatland will be trying to assess during the Six Nations.
Will there be someone who emerges through the tournament as the most obvious candidate? Gatland, to that end, will no doubt train a keen eye on Ireland's Rory Best.
Ireland, as New Zealanders surely now fully appreciated, are going to have a major presence and that's a strong reason in itself to have an Irish captain. But Best ticks way more boxes than that. After he captained Ireland to their historic win against the All Blacks in Chicago, he struck precisely the right tone. He was happy without losing the plot: he was measured in his praise for both teams and seemed to be precisely the sort of character that would keep the Lions on an even keel when they come to New Zealand.
There was a touch of good-natured humour about his manner, too, and the fact he has been in the form of his life for the last 12 months will push him high in Gatland's thinking.
The other leading candidates are Dylan Hartley, Sam Warburton and Alun Wyn-Jones. Hartley could, on a short tour, be problematic. His discipline is erratic and the Lions can't afford to have a captain who may erupt when provoked.
Warburton is a charismatic leader who was the skipper in 2013 but he can't be sure of his test place. The tour would fall apart if the captain can't win a test place.
Wyn-Jones is an option but would need to be extraordinary in the Six Nations to justify the captaincy.
• Scotland v Ireland
Murrayfield, 3.15am, tomorrow
• England v France
Twickenham, 5.40am, tomorrow
• Italy v Wales
Stadio Olimpico, 2.50am, Monday