It's not often the first game of pool play is the most anticipated, but that's the case this year for All Blacks fans.
Yes, there will be a boilover of historic proportions if either of these teams find a way not to progress from the pool stages, but the result of this game will affect the road to the final.
It's hard to see Canada, Namibia and Italy tipping up the All Blacks and Springboks, so the winner here should win the pool. The winner of the pool will meet the runner up of pool A - likely Scotland or Japan - in the quarter-final. Finishing second in the pool would mean a probable date against Ireland in the quarter-finals.
Both sides have named their strongest possible 23 for the match, and the matchup between the halfbacks could prove to be the most important. Faf de Klerk terrorised the All Blacks defences with they met in July, while Aaron Smith will have to have his wits about him and make the right decisions as the Springboks launch their rush defence.
Match details: Saturday September 21, 9.45pm, International Stadium Yokohama, Yokohama City.
Referee: Jerome Garces
Squads
All Blacks: Beauden Barrett, Sevu Reece, Anton Lienert-Brown, Ryan Crotty, George Bridge, Richie Mo'unga, Aaron Smith, Kieran Read (c), Sam Cane, Ardie Savea, Scott Barrett, Sam Whitelock, Nepo Laulala, Dane Coles, Joe Moody.
Reserves: Codie Taylor, Ofa Tuungafasi, Angus Ta'avao, Patrick Tuipulotu, Shannon Frizell, TJ Perenara, Sonny Bill Williams, Ben Smith.
Springboks: Willie le Roux, Cheslin Kolbe, Lukhanyo Am, Damian de Allende, Makazole Mapimpi, Handre Pollard, Faf de Klerk, Duane Vermeulen, Pieter-Steph du Toit, Siya Kolisi, Franco Mostert, Eben Etzebeth, Frans Malherbe, Malcolm Marx, Steven Kitshoff.
Reserves: Mbongeni Mbonambi, Tendai Mtawarira, Trevor Nyakane, RG Snyman, Francois Louw, Herschel Jantjies, Frans Steyn, Jesse Kriel.
How to watch/stream
The Herald will be live blogging the match, with build-up from 6.00pm, and Radio Sport will have live commentary. Spark Sport coverage starts at 8.45pm. Kickoff is at 9.45pm.