Returning Olympians who know the agony of just losing out on a medal and youthful exuberance will spearhead Japan's challenge in the Sevens tournament as the Tokyo 2020 hosts look to show the sport really has taken off here following the success of Rugby World Cup 2019.

Japan's men's team, which has never finished higher than 15th overall in the HSBC World Rugby Sevens Series, produced one of the biggest shocks in Sevens history last time out as they beat powerhouse New Zealand 14-12 in the pool stage at Rio 2016. They followed that up with a win over France before losses to eventual champions Fiji in the semifinals and South Africa in the bronze medal game left them empty handed.

Chihito Matsui of Japan's men's rugby sevens team trains on June 21, 2021, in Tokyo. (Kyodo)

"Our goal was to get a medal in Rio, so we prepared for that," Yusaku Kuwazuru recently told World Rugby.

"We got to fourth and so we didn't reach our goal, but everyone seems to think we did really well. But we didn't reach our goal, so we weren't that impressed (with ourselves). But looking back on it, I guess we did do well."

Kuwazuru, like many of his teammates had endured the yoyo-like ride experienced by Japan in the World Series as promotion to the elite competition was nearly always followed by relegation.

But as the 15-a-side team showed in 2015 when they famously beat the Springboks in their World Cup, Japan rugby teams benefit from long camps and a focus on one game at a time.

"For six months, we focused on New Zealand and worked on our strategy of how to beat New Zealand. That is probably why we beat them," said Kuwazuru, who captained the team.

With the global coronavirus pandemic having put all forms of sevens competitions on hold, this year's team will be just as prepared and just as focused as they look to take on Fiji, Great Britain and Canada in the pool stage.

"We can't participate at the World Series, which makes it hard to predict which teams are good. Nobody can really judge who is the best right now," said Kuwazuru, who added that the hosts will, of course, "want to win a medal this time."

Chihito Matsui leads a side that contains four returnees to Olympic duty: Kameli Raravou Soejima, Lote Tuqiri, Kazushi Hano and Masakatsu Hikosaka. And the team are hopeful they can once again provide some shocks.

"At a one-off tournament anything can happen, especially in sevens," said head coach Kensuke Iwabuchi, who doubles as Japan Rugby Football Union chairman.

The men's competition will take place from July 26-28 before the women take over at Tokyo Stadium from July 29-31.

New women's coach Hare Makiri shocked some when he left out the experienced Chiharu Nakamura and Yume Okuroda from his squad. But the former Brave Blossoms flanker is hopeful new co-captains Mayu Shimizu and Raichelmiyo Batiwakalolo can help the side improve on their 10th-place finish at Rio.

Mayu Shimizu of Japan's women's rugby sevens team trains on July 24, 2021, at Kumagaya Rugby Stadium in Saitama Prefecture near Tokyo. (Kyodo)

The squad contains a number of youngsters, among them Hana Nagata, who was part of a Japan Development side that played in the Coral Coast Sevens in Fiji in January 2018.

Nagata was joined on that trip by Rinka Matsuda -- daughter of former Japan international Tsutomu Matsuda -- who was named in the squad only to pull out on Saturday with an injury.

The two players took time off from high school to attend and despite their youth and relative inexperience impressed South African referee Rasta Rasivhenge, who was the man in charge when Fiji defeated Great Britain in the men's final at Rio.

"They played really well. They're very skilled and their offloading game is really entertaining," Rasivhenge told Kyodo News. "Japan may be small in stature but they don't commit too many to the breakdown and scored some brilliant tries."

While any medal, let alone gold, may be a tough ask for the women -- who have been drawn with reigning champions Australia, the United States and China -- a good showing will certainly help lift the sport's appeal.

And the more women playing, the more female teams there will be meaning the days of girls such as Matsuda and Nagata having to play with the boys' team while at school will come to an end.

It's a point not lost on Nakamura, who remains a great ambassador for her sport and country despite her disappointment at not playing.

"Because we are the host country, it is a very good opportunity for us to make women's rugby more recognized and to make it one of the biggest sports here (in Japan)," Nakamura told World Rugby.

"In 2019, through the Rugby World Cup, people understood the culture of rugby and the values of the game. This time in Tokyo, it is a great opportunity to showcase the characteristics and core values of rugby to people in Japan."