Title contenders England and Ireland enter the Rugby World Cup fray on Sunday, hoping to lay down a marker after impressive wins from southern hemisphere rivals New Zealand and Australia.
The European rugby headline the second full day of action at the global showpiece event that saw three scintillating games on Saturday after an opening night win for the hosts Japan.Ireland come into the tournament as the world number-one side but injuries to key backs Rob Kearney and Robbie Henshaw have marred their preparations as they attempt to break their jinx of never progressing past the quarter-final stage.
They face their biggest Pool A challengers in Six Nations rivals Scotland, whose back line is studded with British and Irish Lions stars seeking to exploit any weaknesses in the depleted Ireland XV.
Much will revolve around World Player of the Year Johnny Sexton, the Ireland fly-half who comes into the tournament desperately short of match practice and struggling for form.
"He's in really good shape physically, mentally very hungry, and looking forward to a massive World Cup. He's in a really good place," said Ireland's kicking coach Richie Murphy.
Scotland have lost six of the past seven games against the Irish but are scenting an upset in Yokohama. Coach Gregor Townsend has named the most experienced Test team in Scottish rugby history with an astounding 630 caps in the starting XV.
"We have to win all the big moments. We have to win every moment in the game, whether it is a ruck clearance, a tackle, an execution of a pass," said Townsend.- 'Throw up or hang on' -
After the Celtic clash in Yokohama, England take to the field against Tonga looking to show the rest of the field that they are serious challengers for the Webb Ellis Cup.
Eddie Jones' side includes marauding back-row forward Billy Vunipola, who has Tongan parents and whose father and uncle both played against England at the 1999 World Cup.
Jones has picked his strongest possible side for the opening Pool C encounter under the roof at the Sapporo Dome and is sticking to his twin playmaker strategy with Owen Farrell at inside centre and George Ford at fly-half.
The veteran coach described his side's impending journey in typically colourful terms, comparing it to a rollercoaster.
"We are at the top of the ride now, we are looking down -- everyone's nervous, everyone's excited. You get down the first slope, you are not sure if you are going to throw up or hang on," said Jones.
Farrell said England's rugby team was hoping to build on the success of the country's cricketers, who won the World Cup at home and football team which reached the World Cup semi-finals in Russia.
"Whether it was the football World Cup, Cricket World Cup, you see the momentum that gathers back home and I'm sure those teams were able to feed off that," Farrell said.
The first game of the day sees Six Nations strugglers Italy unleash their talismanic number eight Sergio Parisse for his fifth world cup against the lowest ranking team in the tournament, Namibia.
Rugby World Cup organisers will hope Sunday's matches build on the excitement sparked the previous day during three pulsating games that saw Australia overcome a feisty Fiji, France pip Argentina 23-21 and the mighty All Blacks beat the Springboks.
They will also be hoping a powerful typhoon expected to squeeze through the sea between Japan and the Korean peninsula spares the matches as forecast, although some fanzones in the southwest have been closed as a precaution.