A Taiwanese pro-democracy activist has gone on trial in China accused of "subverting state power".
Chinese authorities say Lee Ming-che promoted multi-party rule in group messaging chats.
The 42-year-old activist went missing in China in March and was later revealed to have been detained.
Little information has been given by Chinese authorities, but the case has gripped Taiwan amid already strained relations with China.
His wife Lee Ching-yu, who has led calls for his release, is attending his trial in Hunan province. She had warned he may be pressured to make a confession against his will.
What happened to him?
Mr Lee, an NGO worker, is a well-known democracy and human rights activist in Taiwan.
On 19 March he travelled to the semi-autonomous Chinese territory of Macau, then moved on to the southern mainland province of Guangdong where he went missing.
His wife later held a press conference in Taiwan calling for answers from the Chinese government.
On 29 March, China announced Mr Lee had been detained for "pursuing activities harmful to national security". In May, authorities said he was suspected of "subverting state power", and that he was being held in Hunan province.
A Chinese activist, Peng Yuhua, is also on trial with Mr Lee on similar charges.
What is he accused of doing?
Prosecutors at the Yueyang Intermediate Court in Hunan province, which is posting live updates on the trial online, accused Mr Lee of "attacking Chinese society and encouraging multi-party rule".
They said he did this through an organisation called Plum Blossom Company set up with Mr Peng, and also through posts in a group chat with more than 2,000 members in the popular messaging platform QQ.
Mr Lee was accused of using the medium to organise activities "inciting others to subvert state power" as well.
Mr Lee was seen in a clip recorded at the trial saying he had "no objection" to the charges.
He admitted that he had circulated and written articles that "attacked and wickedly smeared the Chinese government" and "promoted Western-style multi-party democracy" on various social media and messaging platforms.
Mr Lee's family and colleagues have said he did regularly exchange messages with friends in mainland China discussing democracy and China-Taiwan relations, but that he had done nothing wrong and only shared his experiences as an activist.
On Saturday, his wife told reporters: "Please forgive Lee Ming-che if you see him doing or saying something embarrassing in court under duress.
"That is just the result of the Chinese government skilfully extracting a 'guilty confession'," the CNA website (in Chinese) quoted her as saying.
How big is this case?
The case has strained relations between China and Taiwan, which Beijing considers a breakaway province to be reunited with the mainland one day.
It is being watched particularly closely in Taiwan, where many often travel to mainland China for work or holidays.
The incident comes during a period of souring ties which began when Tsai Ing-wen, from the pro-independence Democratic Progressive Party, became president last year.
Ms Tsai has called on Chinese authorities to return Mr Lee safely, and to "not let this case be an impediment" to relations.
"China may perhaps see this as a small matter, but in reality, this is a huge cross-strait issue," she said in an interview (in Chinese) in April.
The spokesman of China's Taiwan Affairs Office, Ma Xiaoguang, previously said the investigation into Mr Lee would be "handled in line with legal procedures".