Ichiro Ozawa, one of Japan's most influential politicians, went on trial in the Tokyo district court Thursday on charges of breaking political fundraising laws.
The BBC reports that the former leader of the governing Democratic Party of Japan (DPJ) pleaded not guilty to falsifying reports about money handled by his political fund management body in 2004.
Three of his former aides were convicted last week on similar charges, while Ozawa was indicted on 31 January.
The 69-year-old claims the charges, which have deeply divided the DPJ, are politically motivated.
Agence France Presse reports that Ozawa called on the court to halt the proceedings:
This (case) is based solely on testimonies collected by prosecutors' illegal investigation. This (trial) should be terminated immediately.
What the court-appointed lawyers said is not true.
Ozawa, who is at home referred to as the "shadow shogun", leads the biggest faction in the ruling party.
His trial is the first of its kind in Japan, and comes after a panel of citizen judicial reviewers overturned a decision to drop the case due to a lack of evidence.