Yamada was a senior communications ministry bureaucrat when she attended an expensive meal hosted by executives linked to a satellite broadcasting firm, including Suga Seigo, a son of Prime Minister Suga Yoshihide. The 2019 dinner violated an ethics law intended to prevent corruption.
Prime Minister Suga has apologized for the inconvenient timing of Yamada’s departure.
"The resignation of the public relations secretary happened at an extremely important time during Diet deliberations," Suga told reporters on Monday. "I deeply apologize for causing trouble to the public, as well as members of the Diet."
Yamada admitted she had been wined and dined by Tohokushinsha Film Corp, which has a subsidiary involved in the satellite broadcast industry. Her meal cost about $700 dollars.
Civil servants are barred by law from accepting hospitality from anyone who could benefit from their positions. The communications ministry has the authority to award bandwidth usage rights to broadcasters.
Yamada was questioned by opposition lawmakers at a Lower House budget committee session last week. She said the dinner conversation was mainly casual banter.
“We may have discussed the overall situation in broadcasting at the dinner, but I think that we talked about general matters,” she said. “The company wasn’t asking for favors.”
When the scandal broke last month, Yamada initially maintained she would stay put despite calls from opposition parties to step down. As Cabinet Public Relations Secretary, it would have been her job to host a press conference, should it have gone ahead, for Suga to detail the partial lifting of the state of emergency coronavirus restrictions last Friday.
The Prime Minister did not hold a press conference, prompting speculation that he was trying to avoid questions about the scandal. He insists the decision was unrelated.
Yamada was scheduled to face additional questioning from lawmakers on Monday. But she fell ill and was hospitalized on Sunday, before submitting a letter of resignation.
The government's top spokesperson, Kato Katsunobu, maintains that it was Yamada’s choice to step down: "I believe Ms. Yamada made the decision based on her health.
“The prime minister hoped she would continue in her job, but because of Ms. Yamada's physical condition and her own intentions, it was decided there was nothing to do but let her go," Kato said on Monday.
Edano Yukio, the leader of the Constitutional Democratic Party - the largest opposition group – says Suga has not been transparent about the issue.
“Ever since the scandal broke, Prime Minister Suga has failed to give us an explanation. He's avoiding facing up to the problem," says the opposition lawmaker.
More pressure is coming from a civic group that submitted a letter of complaint to the Tokyo District Public Prosecutor’s Office last week. It claims that the type of entertainment the company executives provided to Yamada and other communications ministry bureaucrats amounts to bribery.