What’s stealth intervention? When you have a proxy act on your behalf. The BOJ could use the Bank for International Settlements (BIS), the Japanese postal savings system (Kampo), or even a commercial bank to sit on the bid on their behalf. That attempts to give the market the impression that it is not intervention alone that is holding up the market.
Hard to get too bullish on USD/JPY when BOJ officials express doubt that the strategy can work amid European turmoil…