The secret of Japan's impressive World Cup campaign is down to intense preparation, video analysis -- and iPads, according to forwards coach Steve Borthwick.

The Brave Blossoms are currently challenging for a quarterfinal spot having won two of their three Pool B matches. Eddie Jones' side shocked South Africa in Brighton and, following a tired defeat against Scotland, they rallied to beat Samoa last Saturday.

With the next World Cup taking place in Japan, Jones set lofty ambitions of reaching the last eight in England to help build interest back home. Borthwick has been impressed with the attitudes on show and opened up on the secrets behind their success.

"One is the players prepare really well. In my experience, compared to players elsewhere like England, the Japan players do a lot more video work," Borthwick said during a press conference at the team's hotel on Monday.

"The players have their iPads and computers and they're looking at footage all the time. It's a great credit to the players.

"Great credit has to go to Michael Leitch [captain]. With him and the senior players, they've gradually taken on more responsibility. They're driving the standards and they're willing to address things when things are not right."

"And under pressure they've made great decisions. They've adapted, changed the game well. That leadership group has been communicating extremely well."

Victory against the Springboks -- Japan's first win at a World Cup since 1991 -- saw interest boom with several official Rugby World Cup stores having to close early having sold out of Japan shirts.

"What we set out to do is build a rugby team that Japan can be proud of," Borthwick added. "Their history of the World Cup has not been good -- it's been terrible. The players have taken it upon themselves to inspire the next generation of players."

Japan face the USA in Sunday's final pool match in Gloucester knowing their opponents have a 100% World Cup record over them. The Americans enjoyed victories in 1987 and 2003 and will be keen to end the tournament on a high.

"We know this weekend, in that regard, is going to be a big challenge. The US have some very strong players, very powerful players. We know we need to be at our best this weekend," Borthwick said.

Hooker Shota Horie added: "We need to study closely how America scrums so we know what to expect. We kept it simple against Samoa, going back to what we do best which is to outwork our opponents. We didn't try to outsmart ourselves. It all comes down to preparation and how well we can stay focused for the game."