Two leading coaches believe the Japan Rugby Football Union does not understand just how much of an impact this year's Rugby World Cup will have and say the policies currently in place will see rugby here suffer greatly following the tournament.

Jake White, who led the Springboks to victory in RWC 2007, recently told Kyodo News the increased number of foreigners in the Top League will do nothing to strengthen the Brave Blossoms, while Scott Pierce, who has been involved in Japanese rugby since 1992 as a player and coach, said the lack of a clear pathway for players was a "huge issue."

The JRFU recently said the Top League will be restructured over the next two years in part to make up for the loss of the Sunwolves from Super Rugby. And while the news that a large number of overseas superstars will be playing here from next January has delighted fans, White says it is a disaster in terms of developing local talent.

(Jake White)

"Having been in South Africa in 1995 when we (first) won the World Cup, the ground swell and vibe that comes out of a World Cup is incredible," said White, who will leave his role as head coach of Toyota Verblitz later this year.

"Every guy will want to emulate everything he sees and watches on the field, and for kids in Japan there is going to be a massive chance to interact and intermingle with the best players in the world."

For those inspired by the World Cup, their first chance to watch domestic rugby will come in January 2020 and "Just remember post-2015 how many people wanted to see (Ayumu) Goromaru play," White said. But he is worried the product on offer, while being of a high standard, will not benefit Japan in the long term.

"If you really want to encourage young Japanese boys to play rugby you have to create an environment where they can play."

Teams can currently field up to five foreign passport holders, one Asian passport holder and an unlimited number of foreign-born Japanese citizens, providing (with a few exceptions) they are eligible to play for Japan.

And White admitted that coaches -- who are employed to bring success to their corporate side, rather than worry about the long-term development of the national team -- will pick as many foreigners as they can.

However, he said given rugby's increased exposure following the World Cup, the big-name foreigners are no longer a necessity to sell the game to the Japanese public.

"The JRFU needs to create opportunities for young Japanese boys to play rugby. That's the legacy of the World Cup. The current model simply does not work as you do not have enough places for those that want to play."

White said there needed to be better integration between high school, university and company rugby so the top local talent could be fast-tracked now with an eye to the 2023 World Cup and beyond.

"I can't believe they work in isolation as they all do."

The reluctance of universities, for example, to release their players both to the Top League and the national under-20 team only hinders the development of Japanese talent, the 55-year-old South African said.

"With the numbers here, Japan could pick a really strong under-20s team and look to win that tournament. And that would create a winning habit and teach them to compete at international level."

But instead, universities ring fence their top players who end up making their first-class debuts long after their foreign counterparts, leaving them little time to develop before they are thrown into the cauldron of a World Cup.

Pierce, currently head coach of Kamaishi Seawaves said the JRFU's plan post-2019 has left many coaches with more questions than answers as regards the long-term development of the game.

(Scott Pierce with members of the China women's sevens team and their coach in 2015)

"The big issues are the development of coaching resources, the development of the junior game and multiple pathways," he told Kyodo. "None of those issues have been answered. The JRFU have been forced to make a decision but haven't thought it clearly through and it has led to more confusion."

While much has been made of the introduction of tag rugby at elementary schools, nothing has been said about introducing age-grade club rugby to allow children who do not go to schools with rugby teams to play the sport.

"The JRFU has never really pushed development," Pierce said. "They have left it to high schools and universities to run their own systems and the corporates to run their own thing. It's not like overseas where the end target is the national team."

Pierce, 55, who played sevens for both New Zealand and Japan, said rugby needs to look at other sports in Japan that are continuing to grow.

"Look at the example of football. They made sure they went away and learnt how you run the game and they have excellent junior programs in place."

"The JRFU needs to look at the game differently because the World Cup is a magnificent opportunity. But if they do not seize it, we are going to fall behind and lose even more players to other sports."