Hamamatsu - Japan coach Jamie Joseph sprang a surprise on Thursday by naming talismanic captain Michael Leitch on the bench for this weekend's Rugby World Cup clash with Ireland.

The former All Black made four changes to the starting line-up that beat Russia 30-10 in last Friday's Pool A opener, explaining that Leitch would be needed to provide calmness and experience in the closing stages against Ireland in Shizuoka.

Pretoria-born flank Lappies Labuschagne skippers Japan for the first time, becoming the third foreign-born player to captain Japan in a World Cup match after Andrew McCormick and Leitch, who hail from New Zealand.

The hosts are given little realistic chance of winning, despite their heroics four years ago when they stunned South Africa on the way to posting three wins under Eddie Jones.

"Michael has obviously been our captain and if we're going to be successful we're going to need his impact off the bench," said Joseph.

"All great teams have that. We're playing probably the most experienced back three in the world and the players need to be focused on playing the game of their lives - because that's what we need to do to be successful on Saturday."

Asaeli Ai Valu, Lomano Lemeki and Wimpie van der Walt also dropped to the bench, but Joseph denied that his decision to use Leitch as a replacement was influenced by the groin injury the marauding back-rower had been carrying in the run-up to the World Cup.

"If we're in a position to win the match it's probably going to come down to the last five or 10 minutes," he said.

"Michael has only played four or fives games this year but he's a key player. As a coach you need both things - in form players and experienced players coming off the bench."

Joseph's opposite number Joe Schmidt, whose team smashed Scotland 27-3 in their first game, opted not to risk playmaker Johnny Sexton, who is carrying a knock, giving Jack Carty only his second start as playmaker.

But Joseph insisted Sexton's absence would make little difference to an Ireland side who came into the tournament ranked number one in the world.

"We can't afford to be worried if Johnny Sexton is playing or not," he shrugged.

"You don't get to number one in the world with just one or two quality players," added Joseph, who plays Auckland-born William Tupou on the wing for the first time in his Test career.

"They are a team in form, we know how tough a challenge beating Ireland will be."

Kiwi-born lock Luke Thompson, at 38 the grand old man of the World Cup, is promoted to the starting line-up, along with Koo Ji-won, Amanaki Mafi and Ryohei Yamanaka.

Asked about comments from Japan prop Yusuke Kizu made in the build-up, accusing Ireland of bending the rules at the scrum, Joseph smiled: "Kizu is a young man - but yes sometimes they're illegal. We know it will be difficult but we've really improved in the scrum and lineout areas."

Teams:

Ireland

15 Rob Kearney, 14 Keith Earls, 13 Garry Ringrose, 12 Chris Farrell, 11 Jacob Stockdale, 10 Jack Carty, 9 Conor Murray, 8 CJ Stander, 7 Josh Van der Flier, 6 Peter O'Mahony, 5 James Ryan, 4 Iain Henderson, 3 Tadhg Furlong, 2 Rory Best (captain), 1 Cian Healy

Substitutes: 16 Sean Cronin, 17 David Kilcoyne, 18 Andrew Porter, 19 Tadgh Beirne, 20 Rhys Ruddock, 21 Luke McGrath, 22 Joey Carbery, 23 Jordan Larmour

Japan

15 Ryohei Yamanaka, 14 Kotaro Matsushima, 13 Timothy Lafaele, 12 Ryoto Nakamura, 11 William Tupou, 10 Yu Tamura, 9 Yutaka Nagare, 8 Amanaki Lelei Mafi, 7 Lappies Labuschagne (captain), 6 Kazuki Himeno, 5 James Moore, 4 Luke Thompson, 3 Koo Ji-won, 2 Shota Horie, 1 Keita Inagaki 

Substitutes: 16 Atsushi Sakate, 17 Isileli Nakajima, 18 Asaeli Ai Valu, 19 Wimpie van der Walt, 20 Michael Leitch, 21 Fumiaki Tanaka, 22 Rikiya Matsuda, 23 Lomano Lava Lemeki