Japan’s defence coach Scott Hansen had some simple advice for his back three ahead of an expected barrage of high balls from Ireland in Saturday’s Rugby World Cup clash: “Just relax and catch it.”

Japan dropped routine catches in their nervy opening 30-10 win over Russia and coach Jamie Joseph said his changes at fullback and winger were aimed at countering an Irish back three he described as probably the most experienced in world rugby.

Opting to add some extra height, Joseph brought in 188cm tall Ryohei Yamanaka at fullback, shifting Will Tupou to the wing and the 177cm tall Lomano Lemeki to the bench.

“Just relax and catch it,” Hansen told a news conference when asked for his advice to the rearranged back three.

“If you think about the tactics of the high ball… if you break it down, it’s more than one man catching it, it’s the detail up front, it’s the pressure on the kick, it’s the way we’ve allowed them to have space and time.”

“Collectively we’ve looked at that. For us, it’s not just on one man but at the end of the day, just relax and catch it.”

Winger Kotaro Matsushima, who scored a hat-trick in the Pool A opener and keeps his place on the right wing, said he was also ready to be tested in the air at the Shizuoka Stadium.

“Yes, I think that our opponent will be giving us pressure, so first thing is to endure that pressure,” he said.

“Even if we lose a ball, by having a connection with the player next to you, we could end with a positive outcome. But first, the player who catches the ball must make sure that he catches it properly.”

Matsushima, who faced Ireland in both 2017 tests when the pool favourites ran out easy winners, said conceding easy penalties could have a “dreadful” outcome with very few chances to score.

Hansen agreed.

“We know they are world class team with a highly efficient attack that attack with the ball in the right areas, at the right time with the right intent,” the New Zealander said.

“We know set piece-wise with the lineout and scrum what they will look to do there.

“They will attack from multiple phases, they hold the ball the most in world rugby and are effectively the most efficient. So the challenge for us, mate, is how we get the ball back and our tactics around that.”