bathrugby.com and James Mortimer 02.Apr.2013Getty Images
The fly-half arrived at the West Country side shortly after kicking the winning penalty in the World Cup final for the All Blacks in November 2011. He has since gone on to make 31 appearances to date, scoring over 150 points, and cementing his reputation for being able to control a game from 10 with his ability to get a backline firing.
Speaking of his decision, Stephen said: "I've had a great time with Bath, but feel it is time for a new challenge in a new league. I'd like to thank everyone at the Club and all the Bath supporters for all the support during my time here, and I'm really looking forward to doing all I can to help us end this season on a high."
Bath Head Coach, Gary Gold, added: "Steve is a good footballer and is a great character to have around. He has brought a lot of experience to the squad in the last couple of years, and we wish him all the best of luck in Japan next season."