4 Dec, 10:19
Grand Slam winners Fiona Coghlan and Nora Stapelton have returned the Women's RBS 6 Nations trophy to Chief Executive John Feehan at the Six Nations offices in Dublin.
This season Munster are nine points clear at the top, but there are only another six between the next five teams.
Celtic Rugby chairman Andy Irvine said: "We had an incredible, tense finish to the regular league campaign last season and the signs are that this year will be even more exciting.
"Munster may have a handy lead at the moment, but they still have to face four of their major challengers in their final six games.
"They have to travel to Wales to meet the Ospreys and the Scarlets and also face two Irish derbies at Thomond Park against Leinster and Connacht.
"They are in the driving seat at the moment in the race for a home tie in the play-offs, but anything could happen in the final few rounds."
Reigning Magners League champions the Ospreys moved into second place with a bonus point win over Connacht at the Liberty Stadium last weekend and have two Welsh derbies to come on top of their fourth clash with Munster this season.
They host the Cardiff Blues on Saturday, April 2 and then travel to face the Newport Gwent Dragons two weeks later.
Both of those games will be shown live on S4C and BBC Wales respectively and 14 of the 18 games from rounds 19 to 21 will be available live for fans to see in Ireland, Scotland and Wales.
The broadcast details for round 22 will be finalised after the penultimate round of fixtures has been completed.
"We have nine games to savour between teams currently occupying the top six places between now and the end of the league season and the results of those matches will have a huge effect on the final four play-off teams," added Irvine.
"With attendances and viewing figures rising, we will be hoping to boost our figures even more over the final six rounds as we head towards breaking through the one million fans barrier for the first time this season.
"The introduction of the Magners League play-off system and grand final concept last season transformed the tournament and the addition of the two Italian franchises, Benetton Treviso and Aironi Rugby, this season has also added another new dimension.
"They may not currently be in contention for a top four finish but they will certainly have a part to play in determining which four teams finally make it to the knockout phase.
"Benetton Treviso have already beaten three of the top six sides at Stadio di Monigo and have two more home games to play.
"Aironi are still searching for their first victory, but have proved a real handful at home and will have a chance to steal some headlines on the last day of the regular season when they host the Ospreys.
"There is also the question of Heineken Cup qualification for the Welsh and Irish teams to consider in the final throes of the season, while the final four rounds could well be the last chances that many players get to convince their international coaches they are worthy of inclusion in World Cup squads.
"But the biggest prize for all the teams will be a place in the Magners League grand final. That has been the dream and the quest all season and we look like having two of Europe's top sides involved in our showpiece event once again on Saturday, May 28."
MAGNERS LEAGUE FIXTURES:
ROUND 19 -
Friday, April 1
Ulster v Scarlets, Ravenhill, 7.05pm (BBC NI/Wales)
Connacht v Edinburgh, the Sportsground, 7.45pm (TG4)
Saturday, April 2
Aironi v Glasgow Warriors, Stadio Zaffanella, 3.30pm local time
Ospreys v Cardiff Blues, Liberty Stadium, 6.30pm (S4C)
Munster v Leinster, Thomond Park, 7.30pm (RTE)
Sunday, April 3
Newport Gwent Dragons v Benetton Treviso, Rodney Parade, 2.45pm (S4C)
ROUND 20 -
Friday, April 15
Newport Gwent Dragons v Ospreys, Rodney Parade, 7.05pm (BBC Wales)
Connacht v Cardiff Blues, the Sportsground, 7.45pm (TG4)
Edinburgh v Aironi, Murrayfield, 7.50pm (BBC ALBA)
Saturday, April 16
Scarlets v Munster, Parc y Scarlets, 6.15pm (TG4/S4C)
Leinster v Ulster, the RDS, 8pm (RTE)
To be confirmed
Benetton Treviso v Glasgow Warriors, Stadio di Monigo
ROUND 21 -
Thursday, April 21
Cardiff Blues v Benetton Treviso, Cardiff City Stadium, 7.05pm (BBC Wales)
Friday, April 22
Ulster v Connacht, Ravenhill, 7.05pm (BBC NI/TG4)
Edinburgh v Newport Gwent Dragons, Murrayfield, 7.30pm
Glasgow Warriors v Scarlets, Firhill Stadium, 8.05pm (BBC ALBA/BBC Wales)
Saturday, April 23
Ospreys v Munster, Liberty Stadium, 6.30pm (RTE/S4C)
Aironi v Leinster, Stadio Zaffanella, 2.30pm local time
Friday, April 29
Newport Gwent Dragons v Cardiff Blues, Rodney Parade, 4.05pm (BBC Wales)
ROUND 22 (TV coverage to be confirmed) -
Friday, May 6
Aironi v Ospreys, Stadio Zaffanella, 8.05pm local time
Benetton Treviso v Edinburgh, Stadio di Monigo, 8.05pm local time
Leinster v Glasgow Warriors, the RDS, 7.05pm
Munster v Connacht, Thomond Park, 7.05pm
Newport Gwent Dragons v Ulster, Rodney Parade, 7.05pm
Scarlets v Cardiff Blues, Parc y Scarlets, 7.05pm