Japan took just six minutes to show its home fans that its Rugby World Cup preparations are on track, scoring a spectacular first try that set the stage for a five-try, 34-21 win over Fiji on Saturday.

The Brave Blossoms' strong performance in their first 2019 Pacific Nations Cup outing was all the more confidence-building for the manner in which it was delivered.

The World Cup hosts scored their points in a variety of ways, while playing defense that withstood most of what the Fijians threw at them.

The win — Japan's first over five-time PNC champion Fiji since 2011, and only the fourth ever — was especially meaningful because it came in a city so badly devastated by the Great East Japan Earthquake and tsunami.

The Kamaishi Recovery Memorial Stadium stands roughly 500 meters from a massive new earth and concrete tsunami barrier across the placid Unosumai River, providing a very real reminder of the events in March 2011.

For one intensely hot afternoon, though, the minds of all 13,135 in attendance were on the Brave Blossoms.

"I think we are building nicely, but there is enough in that match to tell us we have a long way to go," said Japan head coach Jamie Joseph. "We are on our way, but we are not there yet."

Joseph said the team found success by opting not to kick the ball in play, a tactic he envisioned would extinguish the Fijians' open-play firepower.

"We didn't want to kick the ball in the first half unless we kicked it out. We are playing Fiji, which is one of the best teams in the world when it comes to unstructured play," he said.

"We had all the ball and that obviously frustrated Fiji, they couldn't get into their natural game, running at us, offloading, creating opportunities, line breaking.

"It was certainly what we wanted to do today, I think the leaders were able to implement that plan."

One of those leaders, stand-in captain Pieter "Lappies" Labuschagne, said he was very satisfied with the team's performance.

"We knew what we wanted to do and how to execute it, we stuck to the game plan really well and it showed. We managed to put Fiji under a lot of pressure," the South African-born flanker said.

After an early penalty by Yu Tamura, Japan opened its try-scoring account with a wonderful piece of skill.

Flyhalf Tamura lobbed a deft chip kick over the Fijian defense in the corner which, in one fabulous diving effort, Kenki Fukuoka gathered and touched down for the try.

Fiji quickly responded, however, with flanker Semi Kunatani galloping into open space at the halfway line with Levani Botia completing the move with a five-pointer in the 11th minute.

Seven minutes later, Japan crossed the line again. This time it was Kotaro Matsushima who wrong-footed the defense with an angled run, scrumhalf Kaito Shigeno finding him right on time with a nifty pass. After the conversion, Japan was up 15-7.

The Japanese onslaught continued when Timothy Lafaele finished off some skillful short passing in tight space on the right touchline, the center crossing after some fine work between hooker Shota Horie and Matsushima.

In the immediate aftermath of Filipo Nakosi getting a yellow card for a high shot on Fukuoka, Kazuki Himeno scored Japan's fourth try of the first 30 minutes, the conversion giving Japan a 29-7 advantage.

Fiji was able to reduce the halftime deficit to 29-14 with a late try from Sam Matavesi, the big hooker touching down from a short-range maul.

The visiting team immediately blew a wonderful chance to score at the start of the second half when Waisea Nayacalevu was stripped of the ball as he crossed the line, a try-saving tackle by William Tupou denying the bearded winger glory.

Himeno then had a possible second try ruled out when the television match official ruled Amanaki Lelei Mafi had knocked on a couple of phases earlier.

Japan crossed again in the 55th minute when Matsushima toed a spilled Fiji ball ahead before diving to score. Tamura's missed conversion left the score at 34-14.

A rumbling maul try by Matavesi and conversion cut the lead to 13 with approximately 20 minutes to go, but with game slowing due to the heat and substitutions, the Brave Blossoms emerged deserving victors.