With Japan once again the darling of world rugby, thanks to the exploits of the sevens team at the Rio Olympics, attention now shifts to the 15-a-side version of the game with the Top League kicking off Friday.

While the players and coaches have been involved in what new Kubota Spears coach Frans Ludeke described as the "longest preseason I have ever experienced," the administrators have also been busy.

This season features a new competition format, a new system of bonus points, the opportunity for teams to play an additional foreign passport holder and the introduction of the "Head Injury Assessment" to ensure, as league commissioner Osamu Ota put it at the league launch earlier this week, "that players come first."

One thing though does remain consistent.

While the likes of the Honda Heat and Munakata Sanix Blues will, in the words of Honda coach Tomoaki Fujimoto look to try and "make it into the top eight," the Panasonic Wild Knights will once again be the team to beat.

Robbie Deans' team has done anything but rest on its laurels in the offseason recruiting some of the biggest names — both foreign and domestic — as it looks to make it four straight league titles.

David Pocock, Taqele Naiyaravoro, Kenki Fukuoka and Yoshikazu Fujita will all line up at some stage for the Wild Knights this season.

But the signing of University of Tsukuba flyhalf Takuya Yamasawa could have an even bigger impact on Japanese rugby.

Yamasawa became the first student to sign for a Top League side while still in college and Deans described it a "significant precedent."

"If players are ready to play at the highest level then let them," he said. "The national team can only be better for it."

Deans said consistency and "maximizing what we can do" would be key to success this year and it was a theme picked up on by many of the other coaches.

"The game is always about consistency," said NTT Communications Shining Arcs head coach Rob Penney.

Penney took his side to a top-eight finish last season despite a lack of big-name players. While he admitted it was a tough ask to take on the big boys with their unlimited resources, he was hopeful of picking up a scalp or two during the season.

"We want to try and create credibility around the playing ability of the club and hopefully have more of our players progress to the Sunwolves and the national team in the future," Penney said.

Yamaha Jubilo and Toshiba Brave Lupus should once again be in the mix for the silverware despite somewhat limited activity in terms of player recruitment.

Yamaha coach Katsuyuki Kiyomiya was his usual feisty self, laying down a challenge of sorts to Panasonic at the preseason launch.

"If we beat Panasonic (in Friday's opening game) then we won't win the championship. But if we lose to them we will win the title. If I had the choice I would choose the former," he said.

For coaches such as Ludeke, Peter Russell at NEC Green Rockets and Kobe Kobelco Steelers' Jimmy McKay, however, the challenge will be to impose their brand of rugby on clubs that have failed to perform over the last few seasons.

"There have been a lot of changes in the last four years," said McKay, who is Kobe's fourth coach in as many years. "We have worked hard on creating a clear identity and hope to play some positive attacking rugby."

Attacking rugby was the theme for many of the coaches at the preseason launch, at which the new format was laid out.

The league will be a simple round-robin this season, with the side on top of the standings on Jan. 14 crowned champion.

Teams will be able to play two foreign players, an Asian passport holder, plus a player eligible to play for Japan (either immediately or once they have completed their three years' residency).

Following in the footsteps of Super Rugby, teams will now get a bonus point for scoring at least three more tries than their opponents.

While the sides have been playing each other during pre-season camps, Ludeke was sure many teams had kept a number of tricks in the bag for the competition ahead.

"There are going to be a lot of different styles played in a very competitive league and that can only be good for Japan," added McKay.

The action kicks off Friday with Panasonic taking on Yamaha in Tokyo and Suntory Sungoliath playing Kintetsu Liners in Osaka, with a further six games slated for Saturday.