Coach: Joe Schmidt
2016 Six Nations: Third
Best Six Nations result: Champions 2009, 2014, 2015.
Outlook: Not long ago, an injury to the likes of Jonathan Sexton would radiate doubt and panic. Not any more. Ireland have a Plan B, and a Plan C. If Sexton goes down, Paddy Jackson and Joey Carbery can step up. Sean O'Brien? CJ Stander and Josh van der Flier are good to go. Devin Toner? How about Ultan Dillane and Iain Henderson. Ireland's strength in depth was impressively revealed in November when the Wallabies came with Grand Slam ambitions. Already beaten and bruised after two epic matches with New Zealand, Ireland ruled out backs Sexton and Robbie Henshaw. Stander carried a head injury. O'Brien pulled up on the morning of the match with a hip complaint. He was replaced by van der Flier, who became man of the match. By halftime, backs Jared Payne, Andrew Trimble, and Rob Kearney were off injured. Back-up halfback Kieran Marmion was on the right wing, five-eighths Carbery was at fullback, Garry Ringrose out of position, and yet the reserves turned the tide. Ireland's Six Nations title defence last year floundered. This time, the Irish go to Scotland and Italy, welcome France, go to Wales, and finish at home against England.
Eyes on: Tadhg Furlong offers so much as a tighthead prop. He made his mark in the two tests against the All Blacks in November, only his second and third starts. Not only was the set-piece safe, but Furlong tore around Chicago and Dublin, making a right menace of himself. Aged 24, he could be Ireland's tighthead for another decade.
Quote: 'Favourites' is a tag that is external to our environment. We try to go less for prediction and more for preparation.
- Joe Schmidt.
Coach: Rob Howley
2016 Six Nations: Second
Best Six Nations result: Champions 2005, 2008, 2012, 2013
Outlook: Wales have the pedigree but do they still have the prowess? They were the favourites a year ago but tripped in the first round when they conceded a late penalty to leave Dublin with a draw. The decider at Twickenham was an anti-climax after Wales gave England a 19-0 head start. The year only got worse. Drubbings in New Zealand mid-year were expected, but not the embarrassing displays at home in November. For most of the year, the Welsh looked like robots. They seemed to be playing to instructions, and were slow to react. It was jarring from a team which used to feature some of the world's most instinctive players. Wales aren't rated contenders this year, but both favourites, England and Ireland, have to go to Cardiff.
Eyes on: Justin Tipuric. The flanker's credentials are brilliant. He represented Wales all through the age grades, played a year for Wales sevens, and made his senior debut in 2011. His problem has been getting a start ahead of Sam Warburton.
Quote: We are not fancied to win it, and we have to show character and do something about that.
- New captain Alun Wyn Jones
Coach: Guy Noves
2016 Six Nations: Fifth
Best Six Nations result: Champions 2002, 2004, 2006, 2007, 2010.
Outlook: France should be considerably more dangerous this campaign, but are still likely to fall short. After the drudgery of last year's average Six Nations, where France had no running game - and scraped wins against Italy and Ireland thanks to penalties - hopes have been raised that coach Guy Noves is striking the right balance. The old flair was glimpsed in November in home defeats to Australia (25-23) and New Zealand (24-19), prompting All Blacks coach Steve Hansen to say: "It felt like the old French rugby team." Encouraging words. But the harsh reality is that France have some way to go. Noves noted France were the "least efficient" attacking team in last year's Six Nations.
Eyes on: Baptiste Serin. The 22-year-old halfback has great potential. Against the All Blacks, he set up a try for No8 Louis Picamoles with an inspirational moment of magic, darting into space and then fooling the New Zealand defence with a no-look reverse pass. He can kick, too.
Quote: They know how to win by being efficient, a bit like New Zealand. They know how to suffer and still end up winning.
- Guy Noves on England.
Coach: Vern Cotter
2016 Six Nations: Fourth
Best Six Nations result: Third 2001, 2006, 2013
Outlook: Trying to rein in the high expectations in Scotland is difficult. Spirits are soaring because Glasgow, who field a full Scotland side, have qualified for the Champions Cup quarter-finals for the first time. Nobody's talking about winning the Six Nations, but nobody's talking about being happy with third again either. Jim Telfer and Alan Tait, the coach and captain of the last Scotland side to win the championship in 1999, regard this team as the best since then. That's hardly a compliment. Last year was the first time Scotland scored more points than they conceded in the Six Nations. Scotland have vastly improved under Cotter, who arrived in 2014. But milestone results still slip from their grasp.
Eyes on: Jonny Gray. How can you keep your eyes off him? An unrelenting engine allows him to pop up all over the field. He attacks rucks, carries, commits to lifting in lineouts, scores tries and makes tackles. Few in his considerable reach get past him.
Quote: There's a buzz about the place but a sense of realism as well. This is going to be tough.
- Vern Cotter
Coach: Conor O'Shea
2016 Six Nations: Last
Best Six Nations result: Fourth 2007, 2013
Outlook: Italy have been reinvigorated under Conor O'Shea and want to prove the historic victory over South Africa in November was no fluke. The Irishman's jovial manner has had a positive effect on the team after the reign of the dour Jacques Brunel. "There's a great harmony," Italy captain Sergio Parisse said. "Conor is a coach who is young, ambitious, intelligent, energetic and very motivated. Above all, he has clear ideas and manages to transmit his positive energy to the group. Recently, we had lost the feeling of togetherness, the happiness of being together in the national team. Now we're working hard."
Eyes on: Michele Campagnaro. He made a splash in his Six Nations debut against Wales in 2014, scoring two tries with a man-of-the-match performance in a 23-15 defeat. Injuries stymied hopes he would live up to that early promise. He was out for nearly all of the 2015 competition but the 23-year-old centre was Italy's best player last year.
Quote: We will have to work harder than our opponents, playing from the first to the last minute. That's what I'm expecting.
- Conor O'Shea.
Coach: Eddie Jones
2016 Six Nations: Champions
Best Six Nations result: Champions 2000, 2001, 2003, 2011, 2016
Outlook: England have to be the pre-competition favourites after their perfect 2016, although away games in Cardiff (round two) and Dublin (round five) mean a repeat title defence or even a Grand Slam will be hard-earned. Injuries are testing the depth of Eddie Jones' squad but England has a large pool of players to dip into and back-ups have flourished under Jones, giving him two players - at least - in most positions. Current form suggests the title could be settled in a Dublin shootout between Ireland and England in the final game of the competition, a mouth-watering prospect given the English could also be looking to clinch a world-record 19th straight win that day. It was Ireland, don't forget, that brought to an end New Zealand's record 18-match winning run in November.
Eyes on: Maro Itoje. So impressive was his first season in international rugby that Itoje, England's athletic and powerful lock, was voted the Breakthrough Player of the Year at the World Rugby awards in November. The 22-year-old Itoje may need to show his versatility in the Six Nations, however, with Jones potentially deploying him as a blindside flanker now Chris Robshaw is out of the competition because of injury. Robshaw has been one of England's best players in the Jones era but the mobile Itoje's presence in the back row could give the team a new dimension.
Quote: If you get complacent, you get a kick up the arse. We're doing everything we can to ensure there is no complacency, but there is no magic solution because praise makes you weak, doesn't it?
- Eddie Jones
Odds: 4-5 AP