Sonny Bill Williams' first New Zealand rugby coach is expecting a scene out of Gulliver's Travels when the giant midfield back descends on Japanese rugby.

Tabai Matson was Canterbury's backs coach when Williams arrived in Christchurch in 2010 from Toulon.

Once a bullocking midfielder himself, Matson spent six years as a player and then head coach at the Yamaha club in Japan. He has some advice for his former charge.

"Just to do what he did here," said Matson, who has graduated to head coach of the Canterbury team. "Become a good team man, get to know the players and just play well. He's going to dominate and, for him, it's going to be like going to Lilliput.

"It's going to be carnage and I'm actually looking forward to seeing a highlight reel of him offloading against smaller people."

Not assimilating into the Japanese culture was where most hired guns went wrong, Matson said.

However, the brief nature of Williams' lucrative 12-game contract with the Panasonic Wild Knights meant that would not be an issue.

"And the good thing for him is he's going at the money end of the season and going to be playing, relatively, big games. Playing earlier in the season would've been a waste of time for him," Matson said.

With little or no kicking in the Japanese top league and matches played at a frantic pace, Matson said Williams would flourish.

The lack of physicality would also keep him fresh for a return to the NRL next year.

"In the six years I played there, there were only four games where I woke up feeling like I'd played a Super [Rugby] game. You know, where I woke up going ‘oh Lord, I've just been beaten up'," said the veteran of 58 games for the Crusaders.

"So he's going to dominate the collisions and he's going to run more."

What Williams might find difficult was being stuck at his team's Ota base, about 80 kilometres from Tokyo.

Matson was player-coach during his last three years at Yamaha and made a point of doing all the coaching in Japanese.

"You could be the greatest rugby coach and player in the world and if you came to Christchurch and said ‘hey lads this is how we do it where I come from' and you did it through a translator, we'd tell you to get stuffed.

"It's no different there [in Japan]. No different at all."

- © Fairfax NZ News