In what is set to become a landmark development in Japan's notoriously opaque criminal justice system, the Lower House passed an amendment Friday to mandate full recordings of criminal interrogations, introduce a plea bargain system and expand the use of the wiretap law.

After deliberations in the Upper House, the amendment will likely be approved during the ongoing Diet session and is expected to take effect within three years.

If passed, the revised bill will mark Japan's first-ever obligatory recording of criminal interrogations. Currently, recordings are made by prosecutors on a voluntary basis only.