After a warm-weather training camp in Portugal, the Irish will take on England at Twickenham with a double header against Wales to follow.
And while there is plenty of interest in who will get the final places in the squad, just as intriguing is what Schmidt will go for as his first-choice XV.
Perhaps the biggest call of the lot will be in the midfield, with Bundee Aki and Robbie Henshaw having monopolised the inside centre spot over the last three years.
Respectively Aki and Henshaw have started 17 and nine matches for Ireland over the last three years, making up 26 of the 33 Tests played in that time.
While both are capable of playing elsewhere, including together, it may come down to a straight decision between them to partner Garry Ringrose, the only player to start more regularly in the centres for Ireland in that period.
With that in mind, it is revealing to look at their respective performances for Connacht and Leinster, where the two have been so influential.
Of course Henshaw started his career in Galway, and played alongside Aki in the midfield in their 2016 title run.
A look at their efforts last season and it is clear they fulfil similar, if not identical roles for their provinces.
Despite being slightly smaller in terms of stature, Aki still packs an almighty punch and is often used to open up space for those outside him.
Averaging just over three metres per carry, he has a slight edge on Henshaw, although both are invaluable in the role.
Defensively, both rate very highly, with a tackle success in excess of 85 per cent, although in this category it is Henshaw who has the narrow advantage.
The main disparity between the two is in the turnover battle, with Aki recording ten last season to just four from Henshaw. Even bearing in mind the extra minutes played by Aki, he still averages a turnover every 70 minutes, to one every 145 for Henshaw.
That of course can be in large part to the tactics employed by Connacht and Leinster, although Aki’s stockier frame may also lend itself to jackaling a little more than his Leinster counterpart.
One area where Henshaw will have the advantage is his relationship with Ringrose, his Leinster teammate with whom he has built a strong rapport.
However since 2016, the trio have all shown they are capable of stepping up to the highest level, giving Schmidt the perfect headache ahead of Japan.
SCOTTISH BACK-ROW BATTLE
Scotland had a tough time of it in Nice last weekend as they struggled to contain a powerful French forward pack in a 32-3 defeat.
One player to emerge with credit was Edinburgh’s Jamie Ritchie, racking up 25 tackles in an all-action defensive display.
His Edinburgh teammate Magnus Bradbury did not feature in the game but started at No.8 in Scotland’s Guinness Six Nations finale against England, scoring a third try in seven Tests.
While Scotland have plenty of versatile options in the back row, Bradbury could be pushing for the No.8 shirt for the opener against Ireland.
One potential rival for the jersey is another youngster, Matt Fagerson.
The Glasgow Warriors forward, younger brother of prop Zander, won his fourth cap off the bench in France, doing his best to stem the tide.
Similarly versatile to Bradbury, although perhaps more of a No.8 by trade than his Edinburgh counterpart, Fagerson established himself as one of the key men in Glasgow Warriors’ path to the Guinness PRO14 final.
Both players are ferocious tacklers and in the long term may be answers to some of Scotland’s carrying struggles.
Gregor Townsend still has a lot of big decisions to make over his squad, with a host of back-rowers in the mix. Fagerson and Bradbury are two who could be making a big impact by the time he settles on a final 31.