Perenara said he has always wanted to go back to Japan since his first experience there. Japan is close to New Zealand, and playing in Europe doesn't excite him as much.
The developing core of All Blacks halfbacks was not a 'massive factor' in his decision.
"I was confident in my ability to push other halfbacks in the country to be the best halfback we've got. But we do have a lot of depth."
Perenara said Hurricanes teammate Cam Roigard was returning from his injury, and the rugby he played before his injury was special. Cortez Ratima, Noah Hotham, Finlay Christie and Blues halfback Taufa Funaki would all be pushing for All Blacks spots over the next few years.
"I want to be a part of helping those boys over the next four or five months because I know what it's like being a young guy in the environment, and all the hype at the start."
"The big reason for us was security as a family.
"The opportunity to sign a three-year deal in Japan arose and we didn't have three years here in New Zealand."
He discussed his options with new All Blacks coach Scott Robertson.
"We went back and forth a bit, and he was supportive of my decision to stay or go.
"Having that support from him was encouraging and allowed us to make our decision based on what was going to be good for us as a family and my career."
Another factor was looking at his career after his playing time had ended.
"Hopefully, I do really well with the club and turn it into more, and then some steps after."
He said the Japanese market was challenging to enter despite the perception that it was easy.
"With a lot of players wanting to go there, timing is an important thing."
That timing tied in with joining a club that had yet to perform as well as it wanted with the pool of good players it has. It was exciting to be part of working with them to advance.
He said giving something back to the game when his playing stopped was something he was passionate about.
Coaching was something he would like to do in the future.
"It is the easy answer because it's in my mind. It's the easiest way I can work with young players and, hopefully, help them throughout their careers so they can have the experiences I had with rugby.
"It's something I would like to do but not for a few years yet."
Perenara said that, in reflecting on his career in New Zealand, he believed his potential and talent were lower than those of others.
"But I squeezed nearly everything I got out of what I could and I'm proud of that."
He said he was also proud of his work and of reaching as high as possible.