Japan coach Jamie Joseph named a 33-man squad Wednesday for June's test matches against Italy and Georgia, as the Brave Blossoms get set for a busy year ahead of hosting Rugby World Cup 2019.

"As we head towards the World Cup this is a great opportunity for us to grow our depth and this test match series against Italy and Georgia will be a huge challenge for us," Joseph said in naming the squad.

Michael Leitch will lead the side that includes just one uncapped player in flanker Masakatsu Nishikawa, who turned 31 last week.

"Nishikawa has played consistently good rugby for Suntory for the last two years and shown the mettle and resilience I am looking for," Joseph said. "It's not common to make your test debut at that age but I give you another player by comparison in Frank Bunce who became an All Black at 31 and went on to become the most capped center in New Zealand prior to Conrad Smith."

Nishikawa was one of six back-row forwards named alongside Leitch, Kazuki Himeno, Yoshitaka Tokunaga and Shunsuke Nunomaki of the Sunwolves and Amanaki Lelei Mafi, who will play against the Japanese Super Rugby franchise for the Melbourne Rebels on Friday.

Mafi, lock Samuela Anise and flyhalf Rikiya Matsuda are the only players named who are not in the Sunwolves squad, though Anise and Matsuda were part of the Japan A side that recently won two of three games in New Zealand against Super Rugby development sides.

Joseph said 10 of the players named were still with the Sunwolves in Australia, but that five would fly back to Japan following the game against the Rebels with the other five joining up with the national squad after the match against the Brumbies on June 3.

"The criteria really is all about getting game time," the former New Zealand and Japan international said, adding that there were a number of players — such as Lomano Lava Lemeki and Harumichi Tatekawa — who needed game time following a loss of form or injury.

"In the next two to three weeks, there will be players playing some rugby or no rugby depending on their work load."

The 48-year-old former back-row forward said, the odd injury aside, the team was in a lot better shape than a year ago when it lost twice to Ireland — one of its RWC 2019 opponents — at home.

"We weren't fit enough last year when we played Ireland," Joseph said. "We have periodically been running a lot of fitness tests so the bar is a lot higher and players must reach certain standards to maintain their position. And we saw that last week (for the Sunwolves) against the Stormers where we lasted longer in the humidity and heat."

Joseph also confirmed that John Plumtree — who had a big influence on the Brave Blossoms in November 2017, when they beat Tonga and drew with France — would be back as defense coach.

"John has committed to joining the national team for the June tests and will be part of the Japan coaching panel for the November tests, and we have just about finalized his commitment to 2019," Joseph explained.

"Obviously his recent promotion to head coach of the Hurricanes has seen a change in his personal plans, but we are confident we will have John through the World Cup and the World Cup preparations."

The Brave Blossoms take on Italy on June 9 and 16 in Oita and Kobe, respectively, before they play Georgia on June 23 in Toyota city, and Joseph said they were the ideal opponents given the challenges ahead.

"Italy and Georgia are both set-piece teams with very strong scrums, line-outs and mauls and exactly the type of challenge we need going into games against the All Blacks and England at the end of the year and as we prepare for the World Cup," he said