This season's tournament is poised for a pulsating final day, with both Ireland and England, who meet Scotland at Twickenham, still in title contention.
Here, Press Association Sport looks at some of the key talking points ahead of Wales and Ireland going head-to-head.
Can Wales seal the deal?
Unbeaten since Ireland defeated them 13 months ago, Wales are Europe's form team. The likes of England, Australia, South Africa, France and Argentina have all tried – and failed – to topple them during a national record 13-Test winning run, so confidence is high and momentum considerable.
Warren Gatland said after Wales' fightback victory over France six weeks ago that his players had "forgotten how to lose," and this weekend they have to deliver one more time.
Gatland one win away from record
If Wales win on Saturday, it would clinch a third Grand Slam for the New Zealander and create a new record for any coach in the Five or Six Nations.
Gatland has also guided Wales to a World Cup semi-final and that record unbeaten run during his tenure, which will end after this year's World Cup in Japan. His Six Nations farewell could now be the stuff of dreams.
Ireland capable of spoiling the party
Ireland clinched a Grand Slam in Cardiff 10 years ago, while they also inflicted Wales' only defeat of a 2013 title-winning campaign there and hold a 5-4 advantage from nine previous Six Nations visits to the Principality Stadium.
Ireland can also still land the title – provided they beat Wales and Scotland claim a first Twickenham triumph against England since 1983 – so there will be no shortage of desire.
Battle of the half-backs is key
Ireland could have an important edge at half-back where world player of the year Johnny Sexton and his partner Conor Murray have produced the goods time and time again for their country, even if they have not hit top gear in this season's Six Nations.
Opposite numbers Gareth Anscombe and Gareth Davies represent a fledgling Test partnership in comparison, and Saturday will be their biggest examination so far.
Ireland need to silence Cardiff crowd
In a game that is likely to be decided by small margins, both teams will seek any advantage they can and Wales can feed off the emotion and passion of a 74,000-strong Principality Stadium crowd. When England were dispatched three weeks ago, the place almost lifted from its foundations.
When Wales beat Ireland to win a first Grand Slam for 27 years in 2005, it rocked like never before – or since. Home sweet home? It would be foolish to bet against it.