The education ministry had established a systematic practice for seeking new jobs for retiring bureaucrats via a retired official by around 2013, education minister Hirokazu Matsuno disclosed Monday in a preliminary report on the amakudari scandal.

"We will continue our investigation into the people involved and how they saw the situation so we can understand how the mediation worked," Matsuno said. "I'd like to continue learning more thorough the investigation."

Amakudari (literally "descent from heaven") is Japan's long-ingrained but ethically dubious practice of retired bureaucrats acquiring lucrative jobs in sectors they once oversaw.