This weekend will see the final round of RBS 6 Nations matches, and the fact that three sides can still claim the trophy is testament to the competitiveness of the tournament.
Wales are favourites to win the trophy for the first time since 1994. If they beat Ireland at the Millennium Stadium then they will win the tournament and secure their first Grand Slam since 1978.
If Wales do beat Ireland, all other results become redundant in terms of the title chase.
However, Ireland and France do both have a chance of claiming the trophy if results go their way.
If more than one team finishes on the same number of points, which would happen if France beat Italy and Ireland beat Wales - resulting in all three teams finishing on eight points - then points difference comes into play.
This is the key to Ireland and France's chances of claiming the RBS 6 Nations title.
Wales currently have a points difference of plus 62, while Ireland's is plus 37 and France are back on plus nine.
Therefore, the only way France can win the tournament is for Wales to lose to Ireland, and France to beat Italy by a big enough margin to make their points difference better than either Wales or Ireland.
For Ireland to win the tournament they would have to beat Wales by 13 points or more and hope that France do not beat Italy by a big enough points total to overtake both Ireland and Wales.
If Ireland do beat Wales - regardless of the points difference - they will claim their second successive Triple Crown.
If, in the unlikely event that any two teams are tied in the table on eight points and with the same points difference then the winner of the trophy will be decided on tries scored over the course of the tournament.
Currently Wales lead on that front as well with 15 tries, Ireland have nine tries and France have six.
If the teams still cannot be split on points difference or tries scored, then the trophy will be shared.
At the other end of the table Italy look odds on to receive the wooden spoon, having not won a game in this year's tournament. Their points difference currently stands at minus 81 and they have scored just four tries.
Scotland and England have just one win each to their names. A draw between those two sides would guarantee Italy the wooden spoon. Both England and Scotland have superior points differences to Italy (England's is plus 23 while Scotland's is minus 50).
Therefore the only realistic way for Italy to avoid the wooden spoon would be if England beat Scotland and Italy beat France by enough points to better Scotland's points difference.