It was the first public appearance since October for Choi Soon-Sil, who has been dubbed Korea's "female Rasputin" for the influence she wielded over the now-impeached president, Park Geun-Hye.
Sporting black-rimmed glasses and a surgical mask that obscured her face, Choi, who has been in custody for the past seven weeks, was brought to the Seoul Central District Court in a special prison bus.
Television footage showed her handcuffed and wearing a blue-grey prison outfit with a serial number on the chest as she was taken off the bus and led into the court building by a female guard.
Minutes later she entered the courtroom - minus the mask and handcuffs - and sat down next to her lawyer, her head lowered.
Choi, 60, is charged with pressuring big businesses to pay money to foundations that backed Park's policy initiatives.
Choi denied all charges prosecutors brought against her on Monday and said she did not collude with Park, Yonhap News Agency reported.
Prosecutors have named Park as an accomplice, although she has immunity from prosecution while in office. The scandal has led to Park's impeachment in parliament.
Choi also said she did not want a jury trial, Yonhap said.
South Korean courts normally hold criminal trials presided over by a panel of judges, who deliver a verdict and sentence, while defendants in select cases are given the choice of a jury trial.
Influence-peddling
A long-time friend of Park's, Choi is accused of using her leverage with the president to strong-arm the companies into handing over tens of millions of dollars.
She has denied all the criminal charges against her.
Accusations that Park colluded with Choi formed the basis of an impeachment motion against the president that was passed by parliament earlier this month.
The motion is now being considered by the Constitutional Court which has up to 180 days to make a ruling on whether to endorse or reject the president's ouster.
The last time Choi was seen in public was in late October when she attended a summons at the Seoul prosecutor's office and famously lost a much-photographed Prada shoe in the media scrum outside the building.
Choi was not obliged to turn up for Monday's hearing, which was largely procedural and focused on preparing the way for the trial proper.
But her lawyer, Lee Kyung-Jae, said she had volunteered to appear.
"She has expressed a willingness to participate sincerely in the trial," Lee was quoted as saying by the Yonhap news agency.
Choi was criticised for refusing to attend ongoing hearings of a parliamentary committee investigating the scandal.
Leaked documents
Park is also accused of ordering aides to leak confidential state documents to Choi, who has no official title or security clearance, and allowing her to meddle in some state affairs, including the appointment of top officials.
Choi's late father was a shadowy religious figure called Choi Tae-Min, who was married six times, had multiple pseudonyms and set up his own cult-like group known as the Church of Eternal Life.
Choi Tae-Min befriended a traumatised Park after the 1974 assassination of her mother - whom he said had appeared to him in a dream.
He became a mentor to the future president who subsequently formed a close bond with his daughter that persisted after Park's 2012 election victory.
In a televised apology she gave in early November as the corruption scandal snowballed, Park spoke of her "lonely life" as president and how it had led her to place too much trust in Choi.
Park acknowledged letting her guard down with her long-time confidante, who had helped her through "difficult times".
