Rassie: The 20 different scenarios and how Boks can lose out

GRAPHIC EXPLANATION: South Africa's Director of Rugby Rassie Erasmus has added another layer to the already multifarious scenarios that can play out ahead of the World Cup quarterfinals.

Only two teams - Wales and England - have already booked their places in the play-offs.

With six places in the last eight remaining, the final week of pool action is sure to provide loads of drama.

Perhaps none more so than in Pool B - where South Africa, Ireland and Scotland are chasing two spots.

The permutations seem multiplex.

World Rugby, the organisers of the tournament, sketched six potential scripts.

However, Erasmus suggested there are as many as 20 potential scenarios.

As Erasmus pointed out on Monday, all three teams - South Africa, Ireland and Scotland - can still make it.

Tonga and Romania cannot qualify for the quarterfinals.

Scotland must beat Ireland and deny the Irish a bonus point to finish second on the head-to-head rule with South Africa topping the pool.

If Ireland gets a bonus point and Scotland does not, Ireland will top the pool on the head-to-head rule from South Africa.

A Scotland bonus-point win without Ireland getting anything from the game will see them qualify in second place behind South Africa.

The Springboks would finish top on the head-to-head rule.

If Scotland wins and both teams get a bonus point, then they join South Africa on 15 points and the points difference will determine the top spot in Pool B.

Scotland must win by 21 points or more to claim the top spot ahead of South Africa (South Africa +117, Ireland +122 and Scotland +97).

Ireland would then qualify as runners-up on the head-to-head rule, having beaten South Africa.

If Scotland does not win by such a margin, then South Africa will finish top on points difference and Scotland second on the head-to-head rule.

Ireland will guarantee the top spot if they secure two points from their match against Scotland.

Despite all the deliberations, Erasmus is looking forward calmly sitting back and watching it all unfold.

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"There is no arrogance saying this, but I'd rather sit here than be Ireland," Erasmus said.

"Knowing that [Ireland has] been No.1 in the world all the time and Scotland basically just have to beat them by eight points and they are out of the tournament.

"The score could be 22-12 or 22-13 and Ireland are out of the competition if they don't get a bonus point.

"Of the three teams, we are probably the most comfortable sitting here knowing we have got a two-week rest.

"Look, maybe we have got six months rest if the cards don't fall our way.

"We have got two weeks off where we can analyse all three teams that we can possibly play."

The SARU boss said he sees the Ireland versus Scotland game as a 'nervy' affair, as will the France versus Italy affair.

"I know everybody writes off Italy and though Italy are not used to playing against Southern Hemisphere teams, they are used to playing against Northern Hemisphere teams.

"There are going to be some interesting permutations still in the rest of this World Cup."

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* Additional reporting by @rugbyworldcup