phere ' s ▁annual ▁international ▁series ▁for ▁that ▁region ' s ▁top ▁national ▁teams . ▁From ▁its ▁in ception ▁in ▁ 1 9 9 6 ▁through ▁ 2 0 1 1 , ▁it ▁was ▁known ▁as ▁the ▁Tri ▁Nations , ▁as ▁it ▁featured ▁the ▁hem is phere ' s ▁traditional ▁powers ▁of ▁Australia , ▁New ▁Zealand ▁and ▁South ▁Africa . ▁These ▁teams ▁have ▁domin ated ▁world ▁rank ings ▁in ▁recent ▁years , ▁and ▁many ▁considered ▁the ▁Tri ▁Nations ▁to ▁be ▁the ▁t ough est ▁competition ▁in ▁international ▁rugby . ▁The ▁Tri ▁Nations ▁was ▁initially ▁played ▁on ▁a ▁home ▁and ▁away ▁basis ▁with ▁the ▁three ▁nations ▁playing ▁each ▁other ▁twice . ▁ ▁In ▁ 2 0 0 6 ▁a ▁new ▁system ▁was ▁introduced ▁where ▁each ▁nation ▁plays ▁the ▁others ▁three ▁times , ▁though ▁in ▁ 2 0 0 7 ▁and ▁ 2 0 1 1 ▁the ▁teams ▁played ▁each ▁other ▁only ▁twice , ▁as ▁both ▁were ▁World ▁Cup ▁years . ▁Since ▁Argentina ' s ▁strong ▁performances ▁in ▁the ▁ 2 0 0 7 ▁World ▁Cup , ▁after ▁the ▁ 2 0 0 9 ▁Tri ▁Nations ▁tournament , ▁S AN Z AR ▁( S outh ▁Africa , ▁New ▁Zealand ▁and ▁Australian ▁Rugby ) ▁invited ▁the ▁Argent ine ▁Rugby ▁Union ▁( U AR ) ▁to ▁join ▁an ▁expanded ▁Four ▁Nations ▁tournament ▁in ▁ 2 0 1 2 . ▁The ▁competition ▁has ▁been ▁officially ▁re ch rist ened ▁as ▁The ▁Rugby ▁Championship ▁beginning ▁with ▁the ▁ 2 0 1 2 ▁edition . ▁The ▁competition ▁revert ed ▁to