The High Court has ordered in favour of the WRU and has directed that the Regions should not "prevent, hinder or obstruct" the players from attending training on Monday, Tuesday and Wednesday of next week. They will also be available for training for the whole of the following week.
WRU AUDIO: Roger Lewis speaks after the High Court verdict
In his ruling Judge Havelock Allan QC recognised that the international match is the most important factor and not the politics.
The ruling is based on his decision that the WRU has first and last call on the availability of players for training sessions.
The judge explained that his ruling is binding on the Regions by virtue of the express terms of the Participation Agreement and also by virtue of their membership of the WRU.
The court refused an application from the Regions for leave to appeal against his ruling and the court was told that common sense had prevailed.
The WRU asked the High Court to rule on the issue after the Regions continued to withhold their permission to release the players.
Head Coach Warren Gatland originally wanted 13 potential training days from Monday October the 27th but had reviewed that request for a compromise release to initially include the first three days of next week.
The ruling means the squad will gather on Sunday evening at the Vale of Glamorgan Resort Wales team headquarters to be available for training on Monday, Tuesday and Wednesday next week and for the entire five days of the week prior to the game.
The WRU Group Chief Executive, Roger Lewis, said: "Welsh rugby has right on its side and common sense has prevailed.
"This is a victory for the fans of Welsh rugby. Wales will face the World Champions on November the eighth and we have taken this action to ensure they have time to prepare properly for that historic encounter.
"Wearing the Welsh jersey is a huge responsibility for every man selected to play for Wales and we are obliged to ensure they have every opportunity to give of their best.
"The players and coaches must now be allowed to clear their minds of any concerns about this matter and focus on the task in hand.
"This has been an unfortunate episode, but the court ruling justifies our contention that the request was just and we had right on our side.
"We will now put this matter behind us and focus on the priority of finalising the draft Participation Agreement document over the next few days.
"We are determined to deliver an agreement which is good for rugby and fully recognises the efforts being made by all our Regions to advance the professional game in Wales.
"There will always be issues over which to disagree but I want the supporters to remain confident that the Welsh Rugby Union under my stewardship will always aim to do what is best for the game in Wales."
The High Court hearing took place via a telephone conference between the judge and lawyers in London and Bristol.