The trial of Tadao Koseki, the founder and former chief of mutual aid foundation KSD, and two other former KSD officials will begin May 1, the Tokyo District Court said Thursday.
The opening session of the trial will deal with charges of breach of trust and embezzlement involving the 79-year-old Koseki and two of his top advisers.
The three are also accused of bribing former House of Councilors member Takao Koyama, 57.
Koseki has also been served with an arrest warrant on suspicion of bribing Upper House member Masakuni Murakami, 68.