Prosecutors say that Mr. Ozawa was fully aware of the false bookkeeping by the three aides to cover up questionable funds used in the land deal, and that he authorized the false entry of the transaction in an annual political funds report to the government.
Mr. Ozawa, 69, told the Tokyo District Court on Thursday that he is not guilty.
The three former aides were convicted last month and have appealed.
The scandal has damaged Mr. Ozawa’s ambitions to become prime minister, though he still wields considerable influence within the party.
The trial is likely to take months, with a ruling expected in April.
• From wire dispatches and staff reports
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