They call it Judgement Day, and on Saturday more than 60,000 fans will watch Wales’ four rugby regions in action at the Principality Stadium in Cardiff.
The showpiece of the domestic game in Wales – in its fourth season – will see Cardiff Blues tackle Ospreys followed by Newport Gwent Dragons against Scarlets.
But it is more than an end of season exhibition. Much more.
With two rounds of Pro12 matches remaining, play-off places and top-tier European qualification are on the line as well as local bragging rights.
So here’s a quick guide to the matches, and what’s on the line for the teams.
Blues v Ospreys (kick-off 14:30 BST)
With neither side serious contenders for the end-of-season play-offs, resurgent Blues and faltering Ospreys are fighting for European Champions Cup qualification.
Danny Wilson’s eighth-placed Blues are one spot and three points ahead of their opponents and only one point away from sixth place.
Even if they avenge last November’s 13-6 defeat by Ospreys, the Cardiff region will be relying on Munster and Edinburgh, who play each other on Friday, slipping up.
A win for Blues could set-up a big final day showdown at Edinburgh.
A defeat would see Ospreys miss out on European rugby’s top competition for the first time since the region’s inception in 2004.
They will again be without Wales forwards Justin Tipuric (concussion) and Paul James (eye) while captain Alun Wyn Jones is struggling with a heel injury.
Form Guide: Cardiff Blues are looking for a fifth consecutive win; Ospreys have won two and lost two in their last four matches.
NG Dragons v Scarlets (kick-off 17:00 BST)
After beating Ospreys in Swansea on 26 March, Scarlets looked a solid bet for a top-four finish the end-of-season play-offs.
But home defeats against Blues and Glasgow – the latter a 46-10 hammering – have derailed coach Wayne Pivac’s team.
A glance at the table would suggest Scarlets would be strong favourites against 10th-placed Dragons, but the men of Gwent have pushed everyone close this season – as their 10 losing bonus points attest.
And their 23-21 win over Gloucester in the European Challenge Cup quarter final showed that on their day, Dragons can produce a shock.
Scarlets should finish as Wales’ top side and qualify for the 2016-17 Champions Cup, while that train has long since departed from the Dragons’ station, who will play in the second-tier Challenge Cup.
But a shock result here would leave Pivac’s team vulnerable if Blues beat Ospreys – especially with a tough trip to Munster on the final day.
Form guide: Scarlets have lost their last two league matches, but Dragons have lost their last eight Pro12 games.
What’s at stake for Welsh rugby
Not so long ago Wales was guaranteed three places at Europe’s top table.
In contrast to the national side’s consistent challenge at European level, the regions have barely made a dent.
The last Welsh side to reach the knock out stages of the top flight tournament were Cardiff Blues in 2012.
If things go badly in the final two weeks of the Pro12 season Wales will end up with just one team in the Champions’ Cup next season – the same as Italy.
And that would be a major set-back following the restructuring of the tournament in 2013 and the new agreement for funding of the domestic game agreed in 2013.
On a positive note, two wins each for Blues and Scarlets would secure a second place for Wales in the Champions Cup.
However, Ospreys and Dragons fans might feel parochial interests trump national concerns.