The deposed Iraqi leader walked into the courtroom with a broad smile and took a seat alongside his six co-defendants.
The chief judge, Mohammed Oreibi al-Khalifa, called a prosecution witness to the stand, reversing his Monday decision that the court would not hear more witnesses but instead review the evidence.
Saddam and his co-defendants have pleaded innocent to charges of war crimes and crimes against humanity arising from their role in a military crackdown on Iraq's Kurd population in 1987-88. Saddam and one other defendant are also charged with genocide for the campaign, code-named Operation Anfal, in which the prosecution says 180,000 people, mostly civilians, were killed.
Saddam's army allegedly destroyed hundreds of villages and killed or scattered their inhabitants in a scorched earth campaign against separatist guerrillas.