Fujitsu, Japan's largest IT services company, has admitted that health problems were not the main reason for the departure last year of Kuniaki Nozoe, then president.
The highly unusual clarification was issued after the ousted executive demanded his resignation be nullified.
In a statement at the weekend, Fujitsu said Mr Nozoe had actually agreed to resign after being threatened with dismissal over links with a company of “unfavourable reputation”.
The company had said in September that the president was stepping down “due to illness”.
The clarification and Fujitsu’s announcement that it had dismissed Mr Nozoe from his position as a senior executive adviser marked the company's first substantive comments on an extraordinary dispute over his departure as president.
Japanese media reported on Friday that Mr Nozoe had written to Fujitsu insisting that his resignation be nullified, saying the company had falsely attributed it to health issues.
Fujitsu confirmed it had received a nullification demand, but gave no details of its contents.
Mr Nozoe could not be reached for comment, but Reuters news agency quoted his lawyer, Kei Hata, as saying his client had been and still was in good health and that he had been pushed into stepping down in spite of contesting the allegations of improper links.
In its clarification, Fujitsu said Mr Nozoe had been confronted by board members last September over links through a longstanding business acquaintance with the unnamed company, which Fujitsu had found during a previous investigation was the subject of unfavourable rumours.
The board members had told Mr Nozoe that he could be dismissed, but that an offer to resign would be accepted, Fujitsu said.
“Mr Nozoe understood that, given his position as president, his explanation was inadequate, and he chose to resign,” the company said.
Fujitsu insisted that Mr Nozoe had given “explicit approval” for the announcement that he was resigning due to illness, saying that the former president's health “was indeed suffering” at the time.
The IT services provider said it had not been in a position to make public its doubts about the reputation of the company involved.
“[We] hope it will be understood why [we] did not release the full facts at the time of the announcement,” Fujitsu said.
In his less than two years as president, Mr Nozoe upset some colleagues with his drive to focus the group on the provision of IT services to companies and governments by shedding unprofitable electronics divisions, including its hard disk drive business.