With all bar one of the top 20 sides in action this weekend - be it in Europe or Rugby World Cup qualifiers in Africa and the Americas - there is plenty of scope for changes in the IRB World Rankings.
Russia are the only nation not lacing up their boots, although the matches involving Romania, Tonga and Georgia aren't eligible for the rankings as they do not play Test sides, but the A teams of Italy, Ireland and Argentina respectively.
Of the other 14, only second ranked New Zealand cannot improve their rating even with an emphatic victory over Italy at the San Siro in Milan, given the 10 places and 19.29 points currently separating the two sides.
However, New Zealand could still end the weekend as the number one side - regaining the spot they lost following defeat by the Springboks in July - if a much changed side extend a perfect record against Italy and South Africa lose in France.
This reversal is not dependent on the losing margin for the world and Tri Nations champions in Toulouse, as a defeat by just one point will - allied with a 12th straight All Black victory over Italy - see the Boks lose top spot.
An interesting twist to this encounter is that not one member of the current Springbok side has ever tasted victory over Les Bleus in France, their last win having been a convincing 52-10 success at the Parc des Prince in November 1997.
South Africa currently hold a 1.17 rating point advantage over New Zealand after the All Blacks beat Wales 19-12 last weekend, but a loss by more than 15 points against Les Bleus on Friday could turn that into a 1.41 deficit.
Northern hemisphere pride
In this instance South Africa could also slip to less than two points above Australia - as opposed to the current 6.13 - if the Wallabies keep alive hopes of a first Grand Slam tour of Europe since 1984 by beating Ireland in Dublin on Sunday.
Australia themselves could also fall in the rankings if they slip up against the Six Nations champions on their first appearance at Croke Park, although they would have to lose by more than 15 points for the sides to swap places.
Ireland's own position as the leading northern hemisphere nation in the IRB World Rankings is also under threat, as defeat against Australia - a first loss in 2009 -and a France victory will see Les Bleus take over that mantle and fourth spot.
Declan Kidney's side could actually slide to sixth if Argentina make it two wins in a row against eighth ranked England with victory at Twickenham on Saturday. Sixth ranked Argentina can actually themselves return to fourth if they win and France and Ireland both lose.
Fiji hot on England heels?
England, beaten 18-9 by Australia last weekend, could climb as high as fifth with a victory, but cannot fall below their current position even with a heavy loss. However they could be left a mere two tenths above Fiji, who face Scotland at Murrayfield.
Scotland edged their last meeting with Fiji 22-20 at Rugby World Cup 2003 to seal a quarter final place, and will be looking to get Andy Robinson's reign as coach off to a winning start against the islanders.
They would climb above Fiji into ninth with victory, but defeat puts them at risk of falling out of the top 10 for the first time in two years if Samoa continue their penchant for upset wins over Wales in Cardiff.
If Scotland and Samoa were both to suffer defeats by 15 points then the two would remain in 10th and 11th places with 73.47 points each and separated by mere thousandths. The two would also be locked together if they win by that margin, albeit in ninth and 10th with Fiji sliding two places.
Friend or foe?
A win for Wales in their first meeting with Samoa - their Pool D opponents at RWC 2011 - since 2000 can only improve their rating by a maximum of two hundredths, while defeat at the Millennium Stadium could see them fall two places to ninth, below England and Fiji.
Italy would need to cause one of the biggest upsets in rugby history and beat the All Blacks by more than 15 points to improve their position of 12th. They could, though, slide one place if Canada can overcome Japan by more than 15 points in the first of back to back tests on Sunday.
The 14th ranked Japanese - whose coach John Kirwan will come face to face with his former All Black teammate and roommate in Canada coach Kieran Crowley - will fall a minimum of two places with defeat on home soil in Sendai.
However, they could end the weekend in 18th depending on the losing margin and the outcome of the Uruguay v USA RWC 2011 qualifier in Montevideo the day before. By contrast, Japan can climb to a new high of 13th - swapping places with Canada - if they can beat a side they drew 12-12 with at RWC 2007.
ENC highs and lows
The only other encounter aside from the three Rugby World Cup 2011 qualifying matches - Tunisia v Namibia, Uruguay v USA and Moldova v Czech Republic - that can effect the IRB World Rankings is the European Nations Cup tussle between Austria and Norway in Vienna.
Norway won 11-3 when the sides last met and are the higher ranked of the Division 3B teams in 79th, 11 places and 1.65 rating points above Austria. They will climb above Cameroon with victory, but occupy 73rd if they win by more than 15 points.
Austria would slide to 93rd - above only Luxembourg and Finland - in that instance, but would actually become the higher ranked of the two with victory on home soil with a climb of eight or nine places, condemning Norway to a potential fall to 87th.
The other European Nations Cup match, in Division 3D between Monaco and Cyprus in Menton, will not effect the rankings as the latter are not a full Member Union of the International Rugby Board and therefore not ranked.
On Friday we will look at the impact this weekend's Rugby World Cup qualifiers can have on the IRB World Rankings, which update every Monday at 12:00 UK time.