TOKYO -- When the Brave Blossoms beat Ireland 19-12 in the Rugby World Cup in late September, the Ecopa Stadium in Shizuoka Prefecture exploded in euphoria. Once again, Japan was gripped by rugby fever.

With that win, Japan has risen to eighth position in world rankings, the highest it has ever achieved in this sport. The team advanced to the World Cup quarter-finals for the first time with a 28-21 victory over Scotland at Yokohama on Sunday.

Since the Ireland win, Japan Rugby Football Union Vice President Katsuyuki Kiyomiya has been inundated with calls to create a professional rugby championship series -- an idea he is hoping to bring to fruition over the next two years. His plan is to create a league of 12 teams and bring in players from the Southern Hemisphere.

"This World Cup is a big event Japanese rugby has not experienced before and we are tested on how we take the excitement and enthusiasm created by this event to the next level," said Kiyomiya, who is planning to hold a news conference in Tokyo on Nov. 18 to lay out his plans for such a union by the fall of 2021.

Kiyomiya is a highly respected coach, who worked with top teams such as Waseda University, his alma mater, and Suntory and Yamaha Motor. He is also the father of Kotaro, a professional baseball player with Hokkaido Nippon-Ham Fighters.

Kiyomiya surprised everyone at the end of July, only a month after becoming a JRFU vice president, by speaking of his bold plan to launch the full-fledged rugby union. But Kiyomiya's determination is in part due to knowledge that the current euphoria can quickly fizzle out like it did after the last World Cup in 2015.

Then, Japan also captured the world's imagination when it beat two-time champions South Africa. But the excitement in Japan did not last as the longer-term picture still showed a decline in the sport. The number of people who play rugby in Japan fell by about 30,000 over the past 15 years to about 90,000, one-tenth of those who play football.

"Japan hosting the World Cup made me really think about this," said Kiyomiya. "We need to start working on the scheme immediately after the World Cup ends and I haven't made any negotiation beforehand."

Kiyomiya is flanked by righthand man Masaki Sakaida, a lawyer who joined the JRFU as a board member at around the same time as Kiyomiya. He was one of the people instrumental to the founding of a basketball league in Japan.

But both face a raft of challenges in their quest to upgrade rugby in the country. For one, it will not be easy to lure foreign players to Japan if they already play in a team. Kiyomiya plans to address this by ensuring that the Japanese season does not overlap with that of the Southern Hemisphere's Super Rugby championship which runs from January to June so that star players from, say, New Zealand can play in Japan.

He said: "We will turn the new union into the Pacific Rim union that can generate [annual revenue of] about 50 billion yen [$465 million], to be on a par with the European market."

One of the ways to bring in revenue is through the offering of broadcasting rights. However, the JRFU earns virtually no broadcasting profit from the existing Top League series after costs have been taken into consideration.

In the wake of the thrilling win against Ireland that was widely reported on in U.K. papers, Kiyomiya is hoping to form a partnership with U.K.-based DAZN Group, the operator of the sports streaming service DAZN.

"Japan's win against Ireland has increased the value and I'm excited to find out how match it [broadcasting rights fee] will be," said Kiyomiya. He is optimistic but it remains unclear whether the JRFU will be able to sign a contract with DAZN.

Kiyomiya is also counting on a partnership with advertising and public relations company Dentsu but is unable to agree on the structure of the union. Deviating from Kiyomiya's 12-team idea, Dentsu has said that a six-team championship would work better. Kiyomiya had wanted his 12 teams to play from August to January, whereas Dentsu wants a shorter season.

Another sticking point is that overseas players already in teams may not be able to move over to Japan between their own playing seasons. This is due to the nature of rugby as an extremely physically demanding sport that requires players to be rested between series.

Indeed, England's Rugby Football Union has now enforced in-season breaks, with players limited to a maximum of 35 matches per series to protect their welfare. Clubs that flout this rule will face penalties.

The other problem Japan faces is infrastructure. There are only three purpose-built rugby stadiums and each of Kiyomiya's 12 professional teams will require a home and an operating company. Rugby pitches need to be able to withstand rough play on them, as such other sports teams are often reluctant to let their stadiums be used for rugby.

Despite such challenges, Kiyomiya is focusing on finding partners willing to help him launch his idea. He has traveled around the country and been in contact with Canon Chairman Fujio Mitarai, who is president of the Rugby World Cup 2019 Organizing Committee, and NTT Chairman Hiromichi Shinohara.

He is also on close terms with Saburo Kawabuchi, adviser to the Japan Football Association, who succeeded in creating professional football and basketball leagues in Japan.

"Now is the chance to start a professional league, which enables Japanese spectators to see star players in the World Cup 2019 playing at first hand, right in front of their eyes," said Kiyomiya.