By Peter Biles
BBC News, The Hague
Radovan Karadzic insists he needs more time to prepare his defence
With a nod towards the public gallery, Radovan Karadzic looked distinctly businesslike as he entered courtroom one in The Hague.
His grey and white hair was longer than when he appeared here last year. It was more as he wore it during the Bosnian War in the early 1990s.
Mr Karadzic exchanged a few smiles with one of the security guards deployed to stand over him.
While the judges readied themselves for the appearance of the first prosecution witness, the former Bosnian Serb leader put on his reading glasses and paged through his briefcase of documents.
At last, this trial is properly under way.
Judge O-Gon Kwon outlined the timetable for the remainder of April: the tribunal will sit for three days a week as the first witnesses testify against Mr Karadzic.
'Responsible and reasonable'
The judge signalled that Radovan Karadzic was still trying to stretch out the proceedings.
The prosecution team had said they needed just one hour to question today's witness, Ahmet Zulic. Mr Karadzic however, had told the tribunal that he required four hours for his cross-examination.
Looking ahead to the fourth witness on the list, prosecutors say they need three hours to hear from Herbert Okun, a former United Nations adviser.
Mr Karadzic, on the other hand, wants 14 hours set aside for the cross examination. And so it goes on.
Judge O-Gon Kwon said the chamber expected Mr Karadzic to be "responsible and reasonable". The message was clear. He should not expect to be granted all the time he has asked for.
The first witness, Ahmet Zulic, has given evidence at three previous trials in The Hague, including that of the late Slobodan Milosevic.
This is also his third journey to the Netherlands for the Karadzic case. The two earlier journeys had apparently been fruitless because of legal postponements. So it was no doubt with some personal relief that Mr Zulic eventually made it into court.
His evidence was made up of written testimony as well as answers to the questions from the prosecution.
The evidence was certainly harrowing, though strangely not as compelling as it might have been. It was not clear to what extent he believed that Mr Karadzic was directly involved in the events in Sanski Most in 1992.
Mr Zulic seemed to be challenged by both the technology and the geography of Bosnia as he was asked to identify points on a computer map. He showed little emotion as his evidence was translated by the court interpreters.
He concluded his testimony by saying he was physically disabled as a result of his treatment at the hands of the Serbs in 1992, and the psychological stress was still having its effect on him.
The cross-examination, however, was a rather spirited affair, as Radovan Karadzic began to warm to the task of defending himself.
But the day ended with several minutes of instruction to Mr Karadzic from another of the trial judges, Howard Morrison.
The judge told Mr Karadzic that he needed to be more concise, and suggested several ways in which he could sharpen his skills when cross-examining witnesses.
Mr Karadzic seemed to accept the advice in the right spirit, nodding his head in agreement as he was offered tips for the next session.