Japanese Finance Minister Katayama won't comment on whether there was forex intervention other than on Friday

The 'won't comment' formulation is standard Ministry of Finance practice in Japan, where the finance ministry, not the BOJ, directs intervention and officials routinely decline to confirm or deny specific operations until monthly intervention data are published with a lag. Refusing to rule out action beyond Friday keeps the threat of follow-through alive, a form of verbal intervention that historically has been as much the tool as the actual yen-buying itself. Episodes of this kind tend to follow a sequence: sharp one-sided yen moves, escalating jawboning from the vice finance minister upward, sporadic actual operations, then confirmation in the monthly tally, with the largest intraday reversals typically occurring when suspected intervention hits thin liquidity rather than during the Tokyo morning. The distinction worth drawing is between a lone Friday operation and a sustained campaign: isolated rounds have historically slowed but not reversed a trend driven by rate differentials, while repeated operations paired with a shift in the US-Japan yield gap have had more durable effect. The tells are the pace and size of yen moves versus the levels officials have previously flagged, the frequency of further commentary, and the end-of-month intervention data confirming the scale of what was actually spent. Until then, positioning around suspected intervention zones is the established pattern.