Japanese World Cup sensation Ayumu Goromaru, who will be joining the Reds this season, will be a valuable asset for incoming Japan head coach Jamie Joseph.
The Brave Blossoms will be out to improve last year's World Cup performance when they host the tournament in 2019.
"A big reason why the Japanese team have improved is because a lot of those players have had Super Rugby experience, and they took that to the World Cup last year," Joseph told AFP.
Goromaru's departure from Japanese domestic rugby, "will have a positive impact because he is gaining experience playing for another team and taking those experiences back to Japan".
Joseph takes over from Eddie Jones and will have the prodigious task of improving on the 2015 performances.
"There's no doubt Eddie has done a wonderful job and it's been a big loss for Japanese rugby," said Joseph.
"The victories against South Africa and Samoa and the US at the World Cup have made my job a lot more difficult because they've done so well.
"But luckily I've got three years to prepare before the World Cup [in Japan]. It's going to be a lot of hard work between now and then.
"It's difficult because the player base in Japan – particularly with the quality and experienced players – isn't what I'm used to," Joseph added.