Microsoft Corp. will file on Tuesday an abridged version of arguments its lawyers have sounded since the company's antitrust trial began last September, according to sources familiar with the software maker's strategy. With the case entering the so-called finding of fact stage, Microsoft will submit to U.S. District Judge Thomas Penfield Jackson a document approximately 400 pages in length, focusing on the written direct testimony submitted during the defence's rebuttal phase of the trial. Microsoft, whose witnesses were often buffeted on the stand by lead government lawyer David Boies, wants to direct the judge's attention to the hundreds of pages of documents submitted by its witnesses, the sources said. The belief inside Microsoft is that however successful Boies and the prosecution was in scoring points against defendants on the witness stand, the heart of the defence remains untouched. "Boies was effective [in the courtroom,]" said one informed source. "But he was not effective at meeting the burden of proof." The government and 19 state attorneys general allege that Microsoft illegally leveraged its monopoly in desktop operating systems. Government lawyers are also required to file a finding of fact on Tuesday. The DoJ declined to comment on its plans for filing, according to Department spokeswoman Gina Talamona. In this phase of the trial, each side presents a collection of evidence and arguments it thinks best support its case. The filings are limited to information submitted during the trial, which the judge will review before issuing a ruling. Microsoft and the DoJ will then have 30 days to respond to the findings. The Roshomon-like clash of interpretations between Microsoft and the government is sure to linger on in the finding of fact submissions. Before the trial went into recess earlier this year, lawyers for the two protagonists were publicly gleeful about their performances. Some of that was clearly showboating for the cameras. But whatever private doubts either side may harbour, the next stage of the trial is just as critical to their chances. In the filing of fact, each company has a chance to present its case unhindered by the legal manoeuvring of the other side's lawyers. During the trial, Judge Jackson let each side enter a veritable mountain of evidence into the record. At this stage, he's very likely looking to the two parties to help him ferret out the facts. And Microsoft is said to be confident about its ability to marshal enough hard evidence to shoot down every one of the government's allegations. "This is now our chance," said one of the sources familiar with Microsoft's thinking. "This will give us a chance to step up. When you look [at the evidence] in a complete way -- sentence by sentence with citations -- it's very compelling." The company also will present arguments that it did not foreclose Netscape from shipping its browser, showing that the company distributed as many as 160 million copies of the software. Microsoft will also offer evidence to prove its contention that the company has helped, not harmed consumers. Elsewhere, Microsoft will deny the government's allegation it exerts monopoly power and argue that it has not illegally tied different products together to crush competition. Trial watchers are eagerly awaiting the proposed findings, which will give a sense of each side's perceptions of its strongest and weakest cases. Closing arguments in the case are scheduled to take place Sept. 21. After that, Judge Jackson will rule on Tuesday's filings. Based on that ruling, each side will submit proposed conclusions of law, or each side's interpretation of how the law should be applied to the facts. Take me to the DoJ/Microsoft page.