Authorities call it a thwarted Islamist plot, and say terrorists were responsible for the deaths of some 190 people. But rights groups call it a massacre by security forces, and say several hundred mainly innocent civilians were killed.
The 15 men on trial include a number of businessmen whose original trial on charges of Islamic extremism sparked the Andijon uprising.
Today, they sat in a metal cage in a packed room in Uzbekistan's Supreme Court in Tashkent to hear the multiple charges read out against them -- terrorism, murder, hostage taking, and an attempted coup.
Presiding over the trial, court Deputy Chairman Bakhtior Jamalov said: "Some 200 citizens suffered in connection with these criminal cases. Most of them, or their legal representatives, are here in the courtroom today while the rest of them have stated that they will also participate in further hearings."
Critics, however, say the trial is likely to shed little light on the events in Andijon -- or see the true perpetrators brought to justice. Instead, they're calling the trial a whitewash. They say authorities have used coerced confessions and a campaign of intimidation against those who have tried to tell the truth.
"Those journalists who have been able to go to Andijon have virtually been unable to interview anyone, because people are so frightened to talk to journalists, because they've been told by law enforcement that if they're seen talking to journalists they'll have to pay for that," Maisy Weicherding of Amnesty International said.
The events leading up to Andijon's "Bloody Friday" began three days earlier, with a peaceful protest in the city against the Islamic extremism trial of 23 local businessmen.
Then, on the night of 12-13 May, events took a violent turn. Armed men attacked military barracks and then broke into the city's prison, releasing hundreds of remand and convicted prisoners, including the men on trial.
One of the businessmen, Burkhoniddin Nuritdinov, later described the events of that night. "We'd never seen anything like it before," he said. "I'd never heard any gunfire in my entire life. I was shocked. We went to the corridor and were standing there for a while. The crowd was growing and someone said, 'Let's go downstairs.' We went downstairs, still in shock. We gathered outside. It was very dark, there were no lights on. Someone said: 'If you want, you can go to the hokimiyat [regional administration building]. We will demand our rights'. People marched toward the hokimiyat."
That regional government building, on the city's main square, quickly became the focus of the uprising. Protesters occupied the building, taking some police and local officials hostage.
The news quickly spread, drawing hundreds of ordinary people to the square. The gathering turned into a rally to demand better living conditions.
Then, in the early evening, came the bloodshed.
Witnesses say security forces fired indiscriminately into the crowd. Galina Bukharbaeva of the Institute for War and Peace Reporting spoke from the scene: "There were two or three BTRs [armored personnel carriers] at first. I couldn't tell exactly, because I was running together with the crowd. But then, just five minutes later, more BTRs came, and they started shooting at our backs. Bullets were flying. It was terrifying."
Human rights groups say hundreds of mainly innocent civilians were gunned down that night.
Authorities deny this. They say terrorists were responsible for the deaths of 187 people -- most of them soldiers or local officials. They say the violence was part of a plot to overthrow the government and set up an Islamic state.
But critics say authorities have ensured few people know exactly what happened in Andijon, while the government has rejected calls for an independent enquiry. And groups like Human Rights Watch say activists have been harassed or imprisoned, or have fled the country, following the more than 400 who sought refuge in Kyrgyzstan immediately after the events in May.
(RFE/RL's Uzbek Service/agencies)For RFE/RL's complete coverage of the mid-May events in Andijon, see: "Unrest in Uzbekistan"
Factbox: Andijon Timeline