The Scottish scrum wobbled once or twice against England, but it has mostly been solid and the pack put in a very good shift against Italy. Euan Murray's absence on religious grounds is a big loss, but Geoff Cross is a good scrummager. Ireland, weakened by Cian Healy's suspension, have never been a great scrummaging side at the best of times, so Scotland should be looking to get an edge.
There have also been big improvements in the Scotland line-out since the autumn games, but Ireland are always strong in this area and the return of Donncha O'Callaghan won't do them any harm. Rory Best is a great thrower, too, and Ross Ford will have to try to match that accuracy.
Loading article content
Assessment: Scotland 7/10, Ireland 6/10
THE BREAKDOWN BATTLE
This has become the critical area of every Test match and it will be no different today. The side who win the gain line are well on their way to winning the game. It's also an area of traditional strength for both teams, but Ireland, who sometimes seem to have 15 flankers on the pitch, have certainly had an edge in the past few seasons.
However, Scotland have caught up well. Rob Harley is a real dog in contact, Kelly Brown is having a great championship and Jim Hamilton was very effective against Italy a fortnight ago. But they will have to be at their best again, as Ireland have some top-notch scrappers in players such as Jamie Heaslip, Sean O'Brien and Donnacha Ryan. It's the most important part of the game, but it's almost too close to call.
Assessment: Scotland 7/10. Ireland 7/10
Composure will be the key in the battle of the Jacksons – Scotland's Ruaridh and Ireland's Paddy – at fly-half. Paddy was poor when he was thrown in at the deep end in last year's Heineken Cup final, but maybe that experience has strengthened him. He is a good all-round player, but he will still need the help and guidance of more experienced players around him on his Test debut.
In my book, Ruaridh still lacks the kicking game to be a complete 10. That said, he played much better against Italy than he did against England, so his confidence should be high. He is very much a front-foot player, happiest taking the ball forward. His defensive qualities are often overlooked, but he is a brave and effective tackler as well.
Assessment: Scotland 7/10, Ireland 6/10
Ireland had one of the most feared backlines in world rugby a few years ago. They have lost some of that edge, but Brian O'Driscoll is still a sorcerer with the ball and he can make things happen for the players around him. Ireland cut England open a few times two weeks ago, and only let themselves down with some silly mistakes.
The Scottish back three of Tim Visser, Sean Maitland and Stuart Hogg have been earning rave reviews. It is great to see them playing heads-up rugby, exploiting any chances that come their way, but they have mostly been feeding off opposition errors; I'd like to see Scotland control possession more and bring their strike moves into play.
Assessment: Scotland 6/10, Ireland 7/10
Ireland have been forced to make a lot of changes, but I don't think that makes them any more vulnerable as the newcomers will be familiar with the defensive systems. They are pretty solid in this aspect of the game, although they do tend to give away a lot of cheap penalties. The Irish choke tackle was all the talk of last year's championship, and you can expect to see them bring it into play again.
Scotland's emphasis in defence against Italy was on making the tackles count and I think they did that pretty well, especially in the way they got their second man beyond the ball to disrupt possession. They were also a lot faster off the line than they had been against England, which made a big difference.
Assessment: Scotland 7/10, Ireland 7/10
THE KICKING GAME
The two full-backs, Stuart Hogg and Rob Kearney, are among the most powerful kickers in world rugby. When Hogg puts the ball up in the air it comes down with snow on it and few players have ever kicked so well in attack as Kearney does. Kearney is also so good under the high ball that Scotland will not want to be giving him easy possession.
I have reservations about Ruaridh Jackson's kicking game. I suspect a lot of the tactical kicking will be done by scrum-half Greig Laidlaw, while Conor Murray will do a similar job for Ireland. Paddy Jackson will be Ireland's goal-kicker, which is another big ask for a player who rarely does the job for his club. Laidlaw has been successful with nine of his 10 goal kicks this year, and you can't argue with figures like those.
Assessment: Scotland 8/10, Ireland 7/10