Story highlights Hansen to leave All Blacks after Japan 2019

Has been NZ head coach since 2012

Boasts a win record close to 90%

(CNN) He's arguably the most successful manager in history with a win record of 88.5%, but All Blacks head coach Steve Hansen has announced he will step down after next year's Rugby World Cup.

New Zealander Hansen has led the All Blacks since 2012, a period that has seen them retain the World Cup in 2015 and win six Rugby Championship titles.

He joined the coaching setup in 2004 when he served as an assistant to Graham Henry. During his six-year tenure as head coach, Hansen's side has remained the No. 1 ranked team in the world, winning 96 test matches and losing just eight.

"As only people who have done the job will understand, there are not only heavy demands on yourself, but also on your family," 59-year-old Hansen explained.

Read More