Late in September, 52 Japanese children turned up for an introductory event at Tokyo's Katsushika Rugby School, about five times the intake of the year before.
It was no coincidence that days earlier, Japan's rugby team had stunned South Africa and the sporting world with a last-gasp 34-32 win over the two-time world champions at the World Cup on the other side of the world in England.
"We've never seen such numbers in the past," Moriyuki Hayashi, the school's headmaster, told Reuters.
"The national team not only put rugby on the map overseas, but within Japan as well."
As Japan prepares to host the next Rugby World Cup in 2019, the first time it will be held outside traditional powerhouse nations, organisers hope the infectious success of the team this year turns into a lasting passion for the sport.
Rugby participation in the Asian nation of 130 million people has waxed and waned since its introduction in the mid-to late 19th century by British armed forces personnel posted there.
It has in fact been in decline over the last two decades, hit by the rising popularity of soccer, a falling birthrate and embarrassing defeats on the field.
Players, coaches and officials are aware of the scale of the task to deliver a thriving tournament in 2019, a year before Tokyo hosts the Summer Olympics.
"The rugby population sank like a stone after Japan's 145-17 loss to New Zealand at the 1995 World Cup," said Hiroki Narumi, a 42-year-old coach at the Shinagawa Bamboo Rugby School in Tokyo, and former editor of Japan's Rugby Magazine.
"High schools were particularly hard hit, with national competition entries dropping below 1,000 schools," he said, adding that about double that would enter previously.
According to Japan Rugby Football Union (JRFU) statistics, rugby participation peaked at 167,000 in 1994 but had declined to 106,000 in 2014.
"LIKE A BALLOON"
There are encouraging signs.
Some are only just being felt, after the heroics of the "Brave Blossoms" at the 2015 tournament. The team had the dubious distinction of being the first to win three pool games and yet fail to qualify for the knock-out stages.
"I came along with some friends and it was a lot of fun," said 9-year-old Junior Nnaji, after taking part in the Katsushika Rugby School event.
"I saw how powerful the national team was on TV and I wanted to play as well. I'm a fan of Goromaru," he added, referring to fullback Ayumu Goromaru, who shone against South Africa and became a favourite for his trademark "ninja" kicking posture.
The debut for a Japanese team in next year's expanded Super Rugby competition, hitherto the southern hemisphere's elite provincial competition, could also provide a boost, although a head coach for the Sunwolves had yet to be named by late October.
Eddie Jones, head coach of Japan at the World Cup, stressed the importance of individual brilliance and the broader appeal of an exciting, fast-passing playing style when trying to build a support base for rugby.
"Behind me you have the new sporting heroes of Japan," he said after returning from England with the team.
"It's a great credit to this team. They are the heroes. They've changed Japanese rugby. To finish the tournament ranked ninth in the world, it's an absolutely amazing success story."
But Jones, born to a Japanese-American mother, also sees major challenges to building a lasting legacy.
"This is like a balloon," he said while in England. "It can be popped or it can be a real growth spurt. It's entirely the responsibility of the JRFU.
"To keep improving, things have to change. I couldn't go back after the World Cup and do what I have done for the last four years, because we are not going to improve enough within the current structures. I know enough about rugby to know that."
JONES HARD TO REPLACE
JRFU Chairman Noriyuki Sakamoto believes it will be home enthusiasm, more than visitors pouring in from abroad, that will be key to the success of a tournament expected to cost his organisation around 40 billion yen ($NZ492 million) to stage.
"Attracting Japanese spectators is our first priority. After the national team's success at the World Cup we want people to come and see the game," he told Reuters.
Of the 12 host cities for 2019, 11 have stadiums. Kamaishi, located in an area devastated by the 2011 earthquake and tsunami, is the only one yet to be built.
Sakamoto said there was a need for more equipment and coaches.
"We don't have a specific goal of increasing the rugby [playing] population by 2019...The bigger task is doing something about the current playing environment."
Finding qualified coaches, particularly at the junior level, will not be easy.
Even harder will be replacing Jones, who stepped down after Japan's exit in England.
The JRFU wants someone who has experience of World Cup or Super Rugby success, strong links to the rest of the rugby world and who knows Japanese rugby well.
"You can get a very good coach from overseas, but then there are the cultural aspects, like knowing how the Japanese players click," said Andrew McCormick, who captained Japan at the 1999 World Cup.
"It took years for Eddie to get to this stage and it is going to be a hard job for whoever comes in."
