A former university tutor accused of killing his ex-girlfriend Dunedin student Sophie Elliot has pleaded guilty to manslaughter, but not guilty to murder.
Clayton Weatherston, 33, is charged with murdering Ms Elliott, 22, in January last year.
When asked to enter a plea at the High Court in Christchurch on Wednesday, Mr Weatherston pleaded not guilty to murder, but guilty to manslaughter.
The court on Wednesday lifted a suppression order on the extent of the injuries inflicted on Ms Elliott.
The Crown says Mr Weatherston stabbed or cut Ms Elliott over 200 times and inflicted seven blunt force injuries in what it described as a premeditated attack on her features of beauty.
In its opening statement, the Crown said the killing was carried out in a calm, collected manner which showed significant premeditation.
Prosecutor Marie Grills told the jury that Mr Weatherston drove to Miss Elliott's family home in Dunedin with a kitchen knife in his computer bag.
Ms Grills said Mr Weatherston told the first police officer to arrive at the scene, in a calm normal tone, that he had killed Miss Elliott because of the emotional pain she had caused him during the past year.
However, defence counsel Judith Ablett-Kerr, QC, said Mr Weatherston was provoked by Miss Elliott attacking him with scissors and by the pain their torrid and tumultuous relationship had caused him.
She said Mr Weatherston's personality meant he was ill-equipped to deal with the relationship, which impacted on his personal and professional life.
Ms Ablett-Kerr told the jury it needs to decide if Mr Weatherston is a cold-blooded killer or a man who - as a result of provocation - lost self-control.
Justice Potter emphasised to the jury of eight men and four women the importance of independence, saying they must set aside any media coverage they have heard or seen and speak up if they have engaged in any blog sites pertaining to the case.
The trial is expected to last three weeks.