Former top Chinese politician Bo Xilai has admitted he "made mistakes", but denied all charges against him.
Addressing accusations of covering up the murder of a UK businessman, Mr Bo said he made "serious errors of judgement" but that the charges against him were "exaggerated".
He also denied embezzlement, saying he did not know his wife had stolen public funds until after the incident.
The scandals involving Mr Bo's family have captivated the country.
Before his fall from grace, Mr Bo was the Communist Party chief in the city of Chongqing and one of the most influential men in China.
He is accused of bribery, corruption and abusing his office by using his position to cover up for his wife Gu Kailai, who has been convicted of murdering the businessman Neil Heywood in 2011.
Many analysts assume the outcome of the trial, which will resume for a fourth day on Sunday, has been predetermined - with a guilty verdict.
But observers say Mr Bo has given what, for China, is an unusually vigorous defence.
They say the court hearing is as much about getting rid of a popular politician as it is about criminal wrongdoing.
Foreign media are not allowed into the trial, but the court in the eastern city of Jinan has been posting regular updates on China's micro-blogging site Weibo (in Mandarin) - translated by the BBC.
"On the matter of abuse of office, I made mistakes, this reflected badly on the image of the party and the state. I feel sorry for that," Mr Bo told the Jinan court.
"However I do think the charges against me exaggerated my role in these incidents," he added.
The abuse of office charge stems from accusations that Mr Bo knew and covered up the fact that his wife murdered Neil Heywood in November 2011.
Mr Bo told the court that he had discussed the accusations with her, and his wife told him that she was being framed for the murder.
Much of Saturday's testimony from Mr Bo has centred on two difficult meetings he had with Chongqing's police chief and close associate, Wang Lijun, on 28 and 29 January 2012.
Mr Bo, according to the court's updates, admitted he "did not behave in a calm manner" when Mr Wang accused Gu Kilai of being responsible for Mr Haywood's death.
He told the court he slapped Mr Wang and threw a cup at their second meeting.
"I couldn't control my temper at that moment," the transcript quotes him as saying. "My main thoughts were Wang Lijun wasn't being straight with me. I knew Gu Kailai and Wang Lijun were close. She trusted him most, always telling me nice things about him."
"I always thought Wang Lijun was Gu Kailai's best friend, but Wang suddenly told me Gu committed murder," Mr Bo goes on.
Days after this confrontation, Mr Wang fled to a US consulate to seek asylum, and the scandal became public knowledge.
"I never meant to... protect Gu. I didn't mean to force Wang Lijun away," Mr Bo said.
Wang Lijun also testified at Saturday's proceedings. He has already faced trial for his own actions, and been jailed for 15 years, for defection, power abuse and bribe-taking.
Giving his account of the 29 January meeting at Mr Bo's office, Mr Wang told the court that Mr Bo swore for three minutes before walking round his desk and confronting him.
"He suddenly struck me with his fist and hit my left ear. It was not merely a slap... I found the corner of my mouth was bleeding. Also, there was something flowing out of my ear."
Mr Wang said he told Mr Bo to face the facts, but Mr Bo threw a cup to the floor and said he would never accept it.
Gu Kilai has also testified against her husband. On Friday, Mr Bo described his wife as "insane" because she had implicated him in corruption.
She claimed that wealthy Chinese entrepreneur Xu Ming bought gifts for the family in order to gain favours.
Mr Bo is also accused of embezzling 5m yuan ($800,000; £524,000) in 2000 which had been earmarked for a construction project in Dalian. Mr Bo was the city's mayor in the 1990s.
But at Saturday's hearing he blamed his wife for this, saying he had no knowledge that she had taken the money until later on.
He did, though, admit "some responsibility" for not doing enough to return the money later on. "I feel ashamed," he told the court.
Mr Bo also mocked another prosecution witness, his former colleague Wang Zhenggang, saying his testimony linking him to the embezzled money was "illogical".
Wang Zhenggang said he saw Mr Bo make a call to his wife in which he explicitly said he would funnel money to the family.
But Mr Bo said : "Is this in line with the way an embezzler would think?... It is not even what the most stupid corruption offender would do."
Mr Bo's downfall was seen as the biggest political shake-up to hit China's ruling elite in decades.
The release of trial proceedings during Mr Bo's hearing are in sharp contrast with Gu's trial in August 2012. That hearing took just one day and few details were released.
The Chinese authorities are on high alert for any unrest that might be triggered by Mr Bo's trial - with police closely guarding a security perimeter that spans several miles around the court.
Former Communist Party chief of Chongqing and Politburo member
Mr Bo, the son of a famous Communist Party hero, was once a political high-flyer and described as the nearest China had to a Western-style politician. He ran the coastal city of Dalian and was commerce minister before becoming Party chief of south-western metropolis of Chongqing. He was removed from office following Neil Heywood’s death and was charged with bribery, corruption and abuse of power.
Lawyer and wife of Bo Xilai
Ms Gu, whose father was a prominent revolutionary general, is a well-known lawyer and second wife of Bo Xilai.
She studied at Peking University before opening the Kailai law firm in Beijing. Fluent in English, she and her husband were once one of China's most powerful couples. Last year, she was convicted of Mr Heywood's murder, reportedly over a deal gone wrong, and given a suspended death sentence.
Son of Bo Xilai and Gu Kailai
Educated at the exclusive British private school Harrow, followed by Oxford and Harvard Universities, Bo Guagua has been described as one of China's "princelings" - the descendants of revolutionary leaders often criticised for their lavish lifestyles. Since his parents’ fall, Bo Guagua has remained in the US, where he is preparing to study law at Colombia University in New York. In a statement issued ahead of Mr Bo’s trial, Bo Guagua said he hoped his father would be allowed to defend himself "without constraints".
Former Chongqing police chief
Mr Wang, once a popular police chief and Bo Xilai’s deputy in Chongqing, began his career in law enforcement in the Inner Mongolia region before moving to Chongqing in 2008. He worked closely with Mr Bo but, after an apparent falling out, Mr Wang fled to the US consulate in Chengdu, near Chongqing, where he raised concerns about the circumstances of Neil Heywood’s death. Mr Wang has since been jailed for 15 years, charged with defection, power abuse and bribe-taking.
Mr Devillers is believed to have met Bo Xilai and Gu Kailai in the 1990s while living in Dalian and reportedly helped design street grids in the port city while Mr Bo was mayor. French documents quoted by the Wall Street Journal and New York Times said he also oversaw the running of a villa in the South of France - allegedly belonging to Mr Bo - between 2001 to 2007. He was detained in Cambodia, where he lives, before voluntarily flying to China in July 2012. Reports say Chinese authorities wanted to talk to him as a witness in the Neil Heywood case.
Jiang Feng Dolby
Television presenter and business woman
Mrs Dolby, born in China but now a British citizen through marriage, is well known in China as a state TV presenter. However, after moving to Britain she ran an educational consulting company, which it is claimed helped get the children of wealthy Chinese couples into leading British and American schools and universities. Mrs Dolby was named in official documents quoted by the Wall Street Journal as the manager of a villa in the south of France that is expected to be one of the key pieces of evidence at Mr Bo's trial.
Major seaport in north-eastern China
It was here that Bo Xilai's political career was set on the fast track when he was appointed mayor. Mr Bo was credited with developing Dalian from an unremarkable port city to a showcase for China's economic boom. It was also in Dalian that Mr Bo and Gu Kailai reportedly first met Mr Heywood and Mr Devillers.
Major city in south-western China
Bo Xilai was appointed Communist Party chief of Chongqing in 2007. Wang Lijun, the city’s former police chief, was his deputy. Mr Bo became well-known for a high-profile crackdown on crime and advancing the "Chongqing model" of development, which spent heavily on developing public housing and infrastructure. However, his ambition and flamboyant style earned him enemies and raised eyebrows among party leaders back in Beijing. It was in a hotel room in Chongqing that British businessman Neil Heywood was found dead in November 2011.
A six-bedroom villa in the south of France is expected to play a role in the trial of Bo Xilai. The $3.5m (£2.2m) property in Cannes was allegedly given to Mr Bo as a bribe. It it claimed to have been bought by Xu Ming, a billionaire backer of Mr Bo in Dalian. French documents quoted by the Wall Street Journal and the New York Times state people close to the Bo family have been involved with the villa since 2001. French architect Patrick Devillers, British businessman Neil Heywood and Feng Jiang Dolby, a former presenter on China's state TV, have all overseen the running of the property, the papers said.
Having enjoyed a privileged education at Harrow school, Mr Heywood moved to China in the early 1990s where he learned Mandarin, married his Chinese wife Wang Lulu and started a business career. The father-of-two worked as a consultant to foreign businesses seeking investment in China. It was while living in the north-eastern port city of Dalian in the mid-1990s that Mr Heywood met Bo Xilai - then the city’s mayor - and his wife Gu Kailai. More than a decade later, Mr Heywood was found dead in a hotel room in the south-western city Chongqing - where Mr Bo had since become Communist Party chief. In 2012, Gu Kailai and an aide were convicted of poisoning him because of "economic conflict".