The Bank of Japan publishes minutes following its monetary policy board meetings with a four or five week lag. The minutes expand upon the BoJ's post-meeting announcement.
Investors who want a more detailed description of Bank of Japan opinions will generally read the minutes closely. The MPB may issue a statement after its monthly meeting but the minutes will be much more detailed. In particular they will reveal who voted for and against the Committee's decisions and provide a more detailed description of the MPB's thinking. As such, the minutes are a market mover as analysts parse each word looking for clues to future policy.
Once Every 3-4 weeks.