This is European rugby's Super Saturday, the day when all six nations face off to decide who gets what. Ireland can win the Championship, the Grand Slam and the Triple Crown. They just have to beat England to do it. France will be waiting to pounce if the Irish let it slip. Wales and Italy will be striving to avoid a bottom-of-the-table finish. Scotland will be out to confirm their resurgence on the way to next September's World Cup. There's a lot at stake.
France v Wales, Paris
Welsh rugby is in a difficult place. The six domestic clubs have struggled to negotiate contract extensions with key players; there has been talk of a strike; and coach Warren Gatland has been brought back in an emergency effort to stem a long run of defeats.
They beat a very good Italy in Rome last weekend, and that is good news for Gatland. But a clash with resurgent France in Paris is not the match he would have chosen if he hopes to end the international season in glory.
The French have it all.
A back division led by outstanding scrum-half Antoine Dupont has shown flair, intelligence and talent worthy of the mythic French sides of the past.
Les Blues also boast a pack that can win scrums and line-outs, turn over ruck ball, and score tries.
Back-row Charles Ollivon and lock Thibauld Flament each scored twice in the 53-10 rout of the English.
The Welsh, by contrast, look lost. They have the backs but may not have the power in the pack to disrupt ball supply to the French attack.
Ireland v England, Dublin
The Irish are rated the best team in the world right now. England don't make the top five.
Last weekend's Ireland victory in Scotland was a tough affair, with five first-choice players forced off by injury. Having lost both the squad's hookers, the men in green were obliged to play with three props in the front row. Their throw-ins were handed to CJ Stander.
What they lacked in individual expertise, they made up for in spirit.
"It was immense," said Ireland coach Andy Farrell. "In terms of character, fight and want for each other that's the best game I've ever been involved in."
Farrell will, nonetheless, have to plan without Garry Ringrose and Iain Henderson.
And he will surely anticipate a proud English reaction after their humiliation last week at the hands of the French.
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English full back Freddie Steward says he hopes the "only way is up" for his beleaguered teammates after the record-breaking defeat by France as they seek to spoil Ireland's Grand Slam party on Saturday.
England suffered the heaviest home defeat in their history last weekend as the reigning Six Nations champions ran in seven tries during a 53-10 rout of Steve Borthwick's men.
Having been hammered by France, the world's second-ranked team, they now face Ireland, top of the global standings, as the hosts bid to complete a championship clean sweep in Dublin for the first time since 2018.
Steward, who has been a shining light for England this season, scored their lone try against a rampant France at Twickenham.
"Saturday was pretty bleak and I'd like to think that from there the only way is up and that we'll improve," said Steward.
Scotland v Italy, Murrayfield
Both of these sides will feel peeved. Scotland got off to a dream start, beating England in Twickenham, before taking Wales apart in their second outing.
They lost to Ireland, but without conceding a bonus point. They are, undoubtedly, the most improved side in the competition.
Italy come to Edinburgh trailing three defeats, all by far narrower margins than the scorelines suggest.
They have made enormous strides and have definitively silenced those critics who had been calling for their exclusion from the competition.
Italy have been dogged by injuries and held back by their own indiscipline.
It's hard to see them doing more than giving the Scots a tough time this afternoon.