Amrozi bin Nurhasyim, a 40-year-old mechanic, is the first of 33 suspects accused in the Oct. 20, 2002, bombings on the resort island. It was the world's bloodiest terror attack since Sept. 11, killing at least 202 people.
If convicted, the suspects could be executed under tough new anti-terror laws.
Prosecutors say Amrozi bought bomb-making materials and a minivan used in the attack, making the purchases and helping coordinate the car bombing while on his home island of Java.
The 33-page indictment did not say where Amrozi was the night of the attacks at the Sari Club and Paddy's Bar. But it described him as one of the plotters who talked about the obligations of Muslims on behalf of other Muslims "who have been oppressed and slaughtered by the United States and its allies in Afghanistan, Palestine, Kashmir … and Iraq."
The trial is seen as a test of Indonesia's willingness to crack down on radical Islamic groups in the world's most populous Muslim nation and — like most high-profile trials here — is being televised nationally.
It also could shed light on the inner workings of Jemaah Islamiyah, the al Qaeda-linked group blamed for the carnage on Bali as part of wider campaign to establish a Southeast Asian Islamic state.
A police convoy brought Amrozi to a courthouse packed with spectators including survivors and relatives of the dead. Hundreds of officers, including bomb squads and sharpshooters, stood guard outside the court, a short drive from the tourist strip where the bombings happened. Roadblocks were set up and security force helicopters hovered.
Amrozi got his nickname in the Indonesian media when he grinned and giggled in front of news crews after his arrest last November.
He exhibited none of that cockiness Monday, giving only single-word answers to questions from the five-judge panel, including his age, religion and whether he had a criminal record. He declined twice to address the court.
Prosecutors say they have a confession from Amrozi, testimony from 102 witnesses, and physical evidence such as receipts for the explosives and the chassis of the minivan used in the attack.
But defense attorneys say the case fails to prove Amrozi actively took part.
"If he was only present at planning meetings and listened, that is far from what he is accused of in the indictment," lawyer Wirawan Adnan told the court. "The indictment does not show whether he was a planner or just a foot soldier. We have to conclude the indictment is not complete and is invalid."
The trial was adjourned until next Monday.
Outside the courthouse, about 100 Balinese watched the proceedings on two large outdoor screens, shouting and jeering when Amrozi appeared. About 400 people — mostly journalists and diplomats from countries that lost citizens in the bombings — also were there.
One survivor, Peter Hughes, 54, of Perth, Australia, said the anger he felt at seeing Amrozi soon gave way to relief.
"I became quite calm when I saw his eyes. Because I just felt he knew where he was going to be and he realized the enormity of it all," said Hughes, who suffered burns to 54 percent of his body and damage to his respiratory system.
"I saw a normal person. I saw somebody who thinks his end is coming close," Hughes said.
Wayan Sumerta, a 35-year-old Balinese driver, was furious when he saw Amrozi, saying: "Let's just kill him. He killed our friends after all."
Meanwhile, in the east Java town of Lamongan, four men accused of hiding weapons and explosives for another Bali bombing suspect went on trial in two separate courts. Prosecutors accused them of hiding weapons for Amrozi's brother, Ali Imron. A third brother, Ali Gufron, is also a suspect in the Bali attack.
Jemaah Islamiyah's alleged leader, Abu Bakar Bashir, is on trial in Jakarta for alleged treason. Police have not linked him directly to the Bali attack but have accused him of trying to destabilize Indonesia's secular government with a string of church bombings in 2000.
The group has been blamed for other bombings in Indonesia and thwarted attacks on the U.S. Embassy and other Western targets in Singapore.
On April 25, the State Department allowed the return to Indonesia of diplomatic staff and dependents who had been evacuated when the war with Iraq began.
But it warned: "The U.S. government believes extremist elements may be planning additional attacks targeting U.S. interests in Indonesia, particularly U.S. government officials and facilities."