|Ozawa has been nicknamed Prince of Darkness for his reputation of mastering backdroom deals [EPA]
Ichiro Ozawa, one of Japan's most influential politicians, has gone on trial on charges of breaking political fund-raising laws.
The controversial politician pleaded not guilty on Thursday to the charges that could dent his reputation, regardless of the outcome of the trial.
Three of his former aides were convicted last week over the scandal, which relates to a 2004 land deal.
Ozawa, who has played a pivotal political role for four decades, most recently as a power broker in the ruling Democratic Party of Japan, said the charges appeared aimed at destroying him "politically and socially".
"The charges are based on a statement obtained in an inappropriate investigation and this trial should be terminated at once," he told a panel of three judges.
"One can presume this is aimed at destroying me socially and politically. This is a clear abuse of state power."
Regardless of the trial's outcome, analysts say his influence will continue to wane as a result of generational
shift within his party and public distaste for the old-style shadowy politics of which he is seen as a symbol.
Ozawa's mastery of backroom deals has earned him nicknames of Prince of Darkness and Shadow Shogun.
The trial, expected to conclude in April, centres on charges that a body handling his political funds misreported flows linked to a 2004 land deal and that Ozawa was aware of that.
If found guilty, Ozawa faces up to five years in jail or fines of up to 1m yen ($13,000).
He was credited by many for orchestrating the Democrats' historic victory in the 2009 election but lost a party leadership race in 2010 to then-prime minister Naoto Kan. In June, he failed in his attempt to remove Kan through a no-confidence vote.
Finally, a candidate backed by Ozawa to succeed Kan was defeated by Yoshihiko Noda, a favourite of Ozawa's critics.