For those of us who have been following this story for quite some time, this appears to be good news. From the Daily Yomiuri Online, 4/7/12:
Audio and video recordings of interrogations by prosecutors were carried out in 97 percent of major criminal cases from April 2011 to February 2012, according to the Supreme Public Prosecutors Office.
Of all 69 cases handled by special investigation units at 13 district prosecutors offices nationwide, interrogations were recorded in 67 cases. Of that number, interrogations in 28 cases were filmed in their entirety.
The average length of the recordings was 61 hours, with the longest at 127 hours.
Interrogation recording began a year ago following an evidence tampering scandal involving the Osaka District Public Prosecutors Office.