Two of the top four sides meet this weekend as Neil Doak's Ulster travel to Scotstoun to take on Glasgow Warriors, live on Sky Sports.
A bonus-point victory for the home side, who currently sit second, would guarantee a home semi-final and also give them a chance of a first-place finish, depending on the Ospreys result in Connacht.
Victory for Gregor Townsend's side without a bonus point would leave them vulnerable in the top two as a bonus-point win for Munster, who host the Dragons, could deny them.
Ulster meanwhile are in fourth, a point behind the top three and know that victory in Scotland would see them leapfrog their opponents in the table.
But that in itself might not be enough to secure a home semi as victory for Ospreys and Munster would deny them that privilege.
Anthony Foley's Munster side will be gunning for a four-try victory when the Dragons come to Irish Independent Park, a result that would put them in a strong position to grab a top-two finish.
Table toppers Ospreys head to the Sportsground to take on a Connacht side that are still battling hard for a top-six finish that would bring top-flight European rugby to the club next season.
Pat Lam's side are currently seventh in the standings, four points behind the Scarlets who occupy the all-important sixth spot and one clear of Edinburgh in eighth.
If they can match or better Edinburgh's result then Connacht are guaranteed seventh and a trip to Kingsholm to take on Gloucester Rugby in the European Rugby Champions Cup play-offs.
A four-try victory for Connacht, coupled with a defeat for the Scarlets in Italy against Treviso without a losing bonus point, would see Lam's side leapfrog the Welsh region.
The Welsh side therefore travel to Italy knowing that if they can avoid defeat they will secure a top-six finish but they won't have it all their own way against Benetton Treviso.
Treviso are currently 11th in the table but desperately trying to hold off their compatriots Zebre who are three points behind in 12th.
The higher of the two finishers will secure a spot in the Champions Cup and Zebre head to BT Sport Cardiff Arms Park to take on the Blues knowing that is the ground where they claimed their first, and so far only victory on away soil.
If they can repeat the trick, and Scarlets do the business in Italy against Treviso, then Zebre would be celebrating a trip to the top table of European rugby.
But while Zebre will want Scarlets to claim victory, and with it a top-six finish, Edinburgh are - like Connacht - hoping for Treviso to stun the Welsh side.
Edinburgh are currently eighth, one behind Connacht in seventh and five behind Scarlets and host defending champions Leinster at BT Murrayfield.
Alan Solomons' side will need to get something from the game to have a chance of seventh and a play-off for the European Rugby Champions Cup.
To secure sixth and an automatic spot then they need a four-try bonus point win with Scarlets coming home empty handed from Italy and Connacht failing to win against the Ospreys.
Leinster meanwhile have secured a top-six finish but could be overhauled in fifth the table by Scarlets who are four points behind in the standings.
Now the above can all get pretty confusing so below is a club-by-club breakdown for each fan-base so they know what games to keep an eye out for.
OSPREYS 1ST
Who To Watch: Connacht v Ospreys, Glasgow Warriors v Ulster, Munster v Newport Gwent Dragons
What They Need: A bonus-point win for the Welsh side guarantees them a home semi-final, defeat means that victory for Munster and one of Ulster or Glasgow would see them leapfrog the Welsh side.
GLASGOW WARRIORS 2ND
Who To Watch: Glasgow Warriors v Ulster, Connacht v Ospreys, Munster v Newport Gwent Dragons
What They Need: Like the Ospreys, a bonus-point win guarantees them a home semi-final. However defeat to Ulster would allow the Irishmen to overhaul them and put them third or fourth depending on Munster's result. Victory without a bonus point or a draw also opens the door to Munster to leapfrog them with a victory of their own.
MUNSTER 3RD
Who To Watch: Munster v Newport Gwent Dragons, Glasgow Warriors v Ulster, Connacht v Ospreys
What They Need: A bonus-point win over the Dragons would mean that both Ospreys and Glasgow needed to match that result to hold onto the home semi-final spots. Points difference is unlikely to be a factor as Munster have won a game less than both the sides above them. However a bonus-point win for Ulster in Scotland and a four-point win for Munster would mean Munster needed to hold onto a 17-point advantage to claim a home semi-final.
ULSTER 4TH
Who To Watch: Glasgow Warriors v Ulster, Connacht v Ospreys, Munster v Newport Gwent Dragons
What They Need: It would take an unlikely set of circumstances for a draw to be enough to put Ulster into the top two, both Munster and Ospreys would need to emerge empty-handed from their games. But a bonus-point victory for Ulster would see them leapfrog the Warriors and mean that both Ospreys and Munster would need to win, the former would not need a bonus-point while if the latter did not secure a bonus point, it would come to points difference with Munster currently 17 ahead.
LEINSTER 5TH
Who To Watch: Edinburgh v Leinster, Treviso v Scarlets
What They Need: If Leinster can avoid defeat then they are guaranteed to finish fifth, regardless of Scarlets' result in Treviso. Lose in Edinburgh however and a Scarlets victory could see the Welshmen leapfrog the Irish defending champions.
SCARLETS 6TH
Who To Watch: Treviso v Scarlets, Edinburgh v Leinster, Connacht v Ospreys
What They Need: A bonus-point win for Scarlets guarantees a top-six finish and top flight European rugby regardless of other results. Indeed if Leinster were to also lose to Edinburgh then the Welsh region could even end up fifth. Defeat in Italy for Scarlets changes the picture however as, if they emerge empty handed, then Connacht would need to win, either with a bonus point or by enough points to overcome the 28-point deficit currently in place, against the Ospreys to snatch sixth. It would take something extraordinary for Scarlets to be denied seventh however, they would need to emerge empty handed in Italy and Edinburgh would need a bonus-point win against defending champions Leinster, plus a 67-point swing in the differential.
CONNACHT 7TH
Who To Watch: Connacht v Ospreys , Treviso v Scarlets , Edinburgh v Leinster
What They Need: Connacht need Treviso to do them a favour and beat Scarlets if they are to try and claim a sixth-place finish. More important in all likelihood is securing seventh and a spot in the play-offs for next season's European Rugby Champions Cup. To do that they must match or better Edinburgh's result against Leinster as the Scottish side are currently just a point behind in the standings.
EDINBURGH 8TH
Who To Watch: Edinburgh v Leinster, Treviso v Scarlets, Connacht v Ospreys ,
What They Need: Defeat or a draw for Connacht at home to the Ospreys would open the door for Edinburgh to claim seventh if they can beat Leinster at home. Currently trailing Connacht by a point, Alan Solomons' side are 39 points behind Connacht on points difference so are going to need to better the Irish province's result in all likelihood. Snatching sixth from Scarlets, while mathematically still possible, appears a real long shot.
NEWPORT GWENT DRAGONS 9TH
Who To Watch: Munster v Newport Gwent Dragons
What They Need: The Welsh region are guaranteed to finish ninth in the table but could spoil Munster's push for a home semi-final with a victory that would send the Welshmen into the off season on a high.
CARDIFF BLUES 10TH
Who To Watch: Cardiff Blues v Zebre
What They Need: Cardiff Blues are guaranteed to finish tenth in the table but will be looking for revenge over a Zebre side that claimed their first - and so far only - away victory in the competition last season.
BENETTON TREVISO 11TH
Who To Watch: Benetton Treviso v Scarlets, Cardiff Blues v Zebre
What They Need: Currently three points clear of Zebre, Treviso know that a win would secure them a spot in the European Rugby Champions Cup next season. A draw is likely to be enough as Zebre would then need a bonus point win away from home, something they have never done before, and to make up an 18-point difference. Defeat however opens the door for Zebre to leapfrog them off the bottom.
ZEBRE 12TH
Who To Watch: Cardiff Blues v Zebre, Benetton Treviso v Scarlets
What They Need: Currently three points behind Treviso, Zebre need their Italian rivals to lose at home to Scarlets while they beat the Blues in Cardiff to climb off the bottom and seal a spot in Europe's elite competition next year. Even a draw for Treviso would make their job nigh-on impossible.
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