Japan first five-eighth Kosei Ono is another graduate from the Christchurch Boy's High School first XV.

Japan international Kosei Ono is the new poster boy from the Christchurch Boys' High School first five-eighth factory.

The 28-year-old, who starred in Japan's Rugby World Cup upset win over two-time champions South Africa on Monday, is one of six first-fives to have rolled off the Straven Road rugby assembly line.

Three of them are playing at the current Rugby World Cup tournament. All six have, at some stage, played for the High School Old Boys' club.

Joseph Johnson Aaron Mauger was a goalkicking first-five at Boys' High.

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The remarkable run began with Andrew Mehrtens, who played in the 1995 and 1999 Rugby World Cup editions.

He was followed by Aaron Mauger, Dan Carter, Colin Slade, Ono, who made his RWC debut in 2007 just three years out of school, and Shaun Webb, who represented Japan at the 2011 Rugby World Cup in New Zealand.

Joseph Johnson Colin Slade, playing in the 2015 RWC, was in the Boys' High first XV in 2004.

Carter, Slade and Ono are all playing at the 2015 tournament and Mehrtens is covering the tournament as a television analyst.

Slade and Ono were team-mates in the unbeaten Boy's High first XV in 2004 with Slade wearing the No 10 jersey and Ono playing outside him at second five-eighths.

Mauger, now head coach at English club Leicester Tigers, played most of his top-level rugby at second five-eighths, but was a goalkicking first-five in his CBHS days.

ANNETTE TURNBULL-DEW Shaun Webb pictured playing for High School Old Boys in 2002.

Credit where it's due. Southbridge scion Carter did his early schooling at Ellesmere College, but shifted to CBHS in Year 13 to play first XV rugby.

Carter holds the record for the most points scored in test rugby, 1532. Mehrthens is seventh with 967.

Ono, who was born in Japan but moved to Christchurch when he was three, said: "There seems to be a factory [of first-fives] going on" at CBHS.

CHRIS SKELTON Dan Carter, initially a pupil at Ellesmere College, shifted to Boys' High for his year 13.

He said Boy's High was a perfect place to go for a young rugby player because it had "pretty high standards" and his five years there had been instrumental in his career development.

Christchurch Boy's High School rugby co-ordinator Rob Smith said the school was proud of all its test rugby alumni and the first-five factory record, in particular.

"The boys coming through the programme now are all aware of the players who have gone before them who have worn the number 10 jersey. They all aspire to play at the same high standard,' Smith said.

Andrew Mehrtens played in 70 tests from 1995-2004 including the RWC in 1995 and 1999.

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The current Christchurch Boy's High School first XV first five-eighth, Josh McKay, is already wearing a black jersey. He has been selected in the New Zealand Secondary Schools 2015 squad.

Six members of the 2015 All Blacks Rugby World Cup squad, Carter, Slade, Owen Franks, Luke Romano, Ben Franks and lock Brodie Retallick (the world player of the year), and All Blacks coach Steve Hansen are CBHS old boys.

Sir Graham Henry, the coach of the World Cup winning All Blacks team in 2011, also went to Boy's High in the early 1960s.

FIRST-FIVE FACTS

Christchurch Boy's High School's international rugby first five-eighths.

ALL BLACKS

ANDREW MEHRTENS. 70 tests, 1995-2004. Played at the Rugby World Cup (RWC) in 1995 and 1999.

AARON MAUGER. 46 tests, 2001-2007. Played at RWC 2003, 2007.

DANIEL CARTER. 107 tests, 2003-15. Played at RWC 2003, 2007, 2011, 2015.

COLIN SLADE. 20 tests, 2010-2015. Played at RWC 2011, 2015.

JAPAN

KOSEI ONO. 30 tests, 2007-15. Played at RWC 2007, 2015.

SHAUN WEBB. 35 tests, 2008-11. Played at RWC 2011.