I posted on signs of forex intervention to be aware of:

Reuters have a piece up that covers some points that might be of interest:

  • The decision is highly political. When public anger over the weak yen and a subsequent rise in the cost of living is high, that puts pressure on the administration to respond. This was the case when Tokyo intervened last year.
  • But while inflation remains above the BOJ's 2% target, public pressure has declined as fuel and global commodity prices have fallen from last year's peaks.
  • If the pace of yen declines accelerates and draws the ire of media and public, the chance of intervention would rise again.

More at that link above.

Japan yen notes