The ex-CEO of Japan's disgraced Olympus Corp arrived on Friday for a boardroom showdown with the directors who had sacked him, as the firm's share price leapt on hopes he could play a role in putting a huge accounting scandal behind it.

Michael Woodford, still an Olympus director despite being fired as CEO a month ago and blowing the whistle over the scandal, made a rock-star entrance at Olympus headquarters, pushing past reporters and TV crews to enter the building.

Kyodo news agency quoted Woodford as saying he was ready to return but that the decision was up to shareholders.

Inside the office tower, scene of his abrupt dismissal on October 14, a tense meeting was set to begin, with the Briton confronting some of the directors who unanimously dumped him for what Woodford says was his questioning of some dubious deals.

I want to take the opportunity to look the directors in the eye and tell them what I think is best for the company, Woodford told reporters on the eve of the meeting, having flown back to Japan from a month of self-exile in his native Britain.

Woodford headed into the meeting after news on Thursday night that three directors blamed for the scandal had quit, offering to take some of the worst tension out of the confrontation, but the ex-CEO of the once-proud maker of cameras and medical equipment wants the rest of the board to go as well.

Backed by some big shareholders, Woodford says he is willing to reclaim the top job and lead a clean-up of the firm. And his return to the boardroom helped fuel a sense of optimism that has driven a dramatic rally in Olympus shares this week.

The stock soared more than 25 percent in morning trade on Friday, on track for its fourth day of gains.

Today's rise is just a continuation of those willing to take a risk to make a profit, buying what they think is an oversold share, said Fujio Ando, senior managing director of Chibagin Asset Management.

It's too early to make conclusions about what will happen to the company. The investigations are just beginning, and the management situation is still unclear.

Woodford, who says he was sacked for questioning a string of unusual payments to obscure firms, had fled Japan immediately after his dismissal, citing fears for his safety amid speculation the scandal could somehow involve organized crime.

But this week he returned to the eye of the storm, flying back to meet police, prosecutors and regulators investigating the scandal, which has wiped out about half of Olympus's market value and raised the prospect that it could be delisted from the Tokyo stock market and forced to sell core businesses.

Olympus initially denied any wrongdoing after sacking Woodford, a rare foreign CEO in Japan, but later admitted it had hidden investment losses from investors for two decades and used some of $1.3 billion in M&A payments to aid the cover-up.

Late on Thursday, three directors blamed for the concealment quit their directorships, including former President and Chairman Tsuyoshi Kikukawa, which promised to ease at least some of the worst boardroom tension Woodford could face on Friday.

But the CEO-turned-whistleblower still wants the rest of the board to go, including the new president, Shuichi Takayama, who has said that the current management team is ready to quit only once the path to Olympus's revival became clear.

We, the members of the incumbent management team at Olympus Corporation, will be ready to stand aside once Olympus is on track for recovery, Takayama said in a statement.

Some major foreign shareholders have called for Woodford to be immediately reinstated as CEO, but the 51-year-old himself says he does not believe that will happen at Friday's meeting.

I just hope they understand the game is up and do the decent thing, stop damaging the company. Don't look for self-interest, look for the 45,000 people (who work for Olympus), Woodford told reporters on Thursday.

Have some shame, have some dignity, that's what I want to tell them.

Olympus has until December 14 to straighten out its accounts and report its half-year results to the stock market. If it misses that deadline, it will be automatically delisted.

(Writing by Mark Bendeich; Editing by Miyoung Kim)