Ex-Livedoor finance chief Ryoji Miyauchi is one of the men on trial

One of the men, ex-finance chief Ryoji Miyauchi, admitted the charges.

The four men were arrested earlier this year with Livedoor's founder and charismatic head boss Takafumi Horie.

Mr Horie, who rose to prominence for his willingness to attack Japan's staid and traditional business world, will face trial on his own at a later date.

Speaking on Friday, Mr Miyauchi said: "In principle, I acknowledge that the facts in the indictment are correct."

"I am examining myself over the crime I have committed. I feel very sorry for causing trouble to many people," he added.

Widening net

The four executives standing trial in Tokyo on Friday are Mr Miyauchi, Fumito Kumagai, Fumito Okamoto and Osanari Nakamura.

Two accountants from outside of Livedoor also are on trial.

The rise and fall of Livedoor boss Takafumi Horie has been rapid

According to reports, the other defendants have admitted to some, but not all of their charges.

Livedoor itself is also on trial, and Koichiro Ota, a spokesman for the company, said it was not fighting the charges and had entered a guilty plea.

Along with Mr Horie, the executives have been charged with inflating profits at the internet firm and spreading false financial information about a transaction in 2004.

Livedoor's problems prompted a stock market tumble in January, and led to calls for a shake-up in Japanese securities laws and regulation.

Prosecutors have already been laying out their case against Mr Horie on Friday, saying that he was the main person and driving force behind Livedoor's attempts to inflate its earnings and boost its share price.