It is the most specialised batting role, and one New Zealand have battled for years to get right.
Many have tried and been found wanting.
Look down the list of names of those who have gone in first in recent years. A few reached double figures in test appearances, and that seems a reasonable amount of time to discover whether a batsman truly has the right stuff for the task at high international level.
Taking toll of Zimbabwe or Bangladesh in New Zealand conditions is one thing; it's quite another doing the business in Brisbane, Bangalore or Barbados.
Techniques are examined in a range of situations. Only Mark Richardson, Martin Guptill, Jamie How, Matthew Bell and Tim McIntosh have got past 15 matches since 2000. Richardson, Bell and McIntosh scored two centuries. Guptill's got one, against Zimbabwe, while How achieved four half centuries.
Why the high turnover? Clearly the various selection panels believed the players chosen were not worth persevering with.
Now the current panel, coach Mike Hesson and Kim Littlejohn, have sat between two stools for the first test of the ANZ international series next week. They've gone for an old hand in Fulton and the man for the future, Hamish Rutherford.
Had New Zealand gone hard for experience to start the England series it would have meant a double act of Canterbury's Fulton - who is poised to make his comeback in Dunedin after three years out of favour - and Otago's Aaron Redmond. They are 34 and 33 respectively, but of far greater relevance is they were the leading scorers in the just completed Plunket Shield.
Redmond topped the list with 941 runs at 55.35; Fulton was second with 902 at 56.37 and Wellington's Michael Papps, another specialist opener last sighted in national colours in 2007-08, was third with 802 at 45.
Form should be acknowledged, and Rutherford's is good. He has always wanted to open, talked last week of enjoying innings starting at none for none, and having the chance to set out his stall according to the conditions and quality of the bowling attack.
Temperament is clearly important for an opener. Unflappability, the ability to keep calm if the runs aren't coming and the mindset to treat each ball individually.
Rutherford appeals as a sensible sort and is unlikely to be fazed by that. Even so, there are less taxing introductions to test cricket that can be found.
The alternative argument might best be called the "get 'em in" philosophy. In this, promising players are chosen and left there, on the basis that, A: there's no one better; and B: in time they'll come good, even if they go through the wringer to get there.
Canterbury's Tom Latham is highly regarded, but not a specialist opening batsman. However, that argument would have had him going in first with Rutherford.
Age shouldn't matter. Graham Gooch, an opener of high class, was 40 years, 314 days when he made the last of his 20 test hundreds, 210 against New Zealand at Nottingham in 1994.
The oldest opener doing the test rounds elsewhere is Sri Lanka's Tillakaratne Dilshan, who is 36. Next is India's Virendar Sehwag, a fabulous attacker in his prime but who looks to be running on fumes, at 34.
Where New Zealand once had stability in the form of firstly Bruce Edgar and John Wright, and later, to a lesser degree, Wright and Trevor Franklin, since then it has been a revolving door, or one player getting a smallish run, with a succession of partners.
The best example is Richardson, who played 38 tests from September 2000 in just over four years and went through eight partners in 64 innings.
He opened with fellow Auckland batsman Lou Vincent 17 times; Matt Horne 12 and Bell 10 times. Mathew Sinclair walked out with Richardson seven times and Papps six.
Craig Spearman did the honours five times, as did Stephen Fleming while Adam Parore filled in twice. Hardly a settled process.
In the last 14 months, there has been a reasonable period of stability.
Guptill opened in all 12 tests in that period. He had Brendon McCullum for company in seven of them, including the last six. Daniel Flynn and Rob Nicol did the job in two tests each, BJ Watling in one.
Rutherford's chances of success next week are far better than those of his father, Ken.
In one of the most unfortunate test introductions, 19-year-old Ken Rutherford was sent to the West Indies in their intestinal fortitude-testing prime in 1985. He managed 12 runs in seven innings against Malcolm Marshall, Michael Holding and Joel Garner.
Rutherford the Younger hit an impressive 90 in Queenstown on Thursday. It seems unfair pressure, but fingers will be crossed that the young man can provide a fix to a problem which never seems too far away.