USDJPY and the intervention reflex

[Shadow Trader]

When USDJPY climbs quickly toward levels that policymakers in Tokyo consider too weak for the yen, warnings begin. Officials use phrases that escalate from "watching closely" to "taking appropriate action". Markets pay attention.

Actual intervention involves the Ministry of Finance selling dollars and buying yen, and the move can be violent, with 3 to 5 big figures in minutes. Because the central bank often acts when liquidity is thin, spreads blow out and stops slip heavily.

For scalpers long USDJPY into a rally, this is a nasty risk. A trade with a 6 pip stop can be filled 40 pips away in the worst moments.

Rhetoric ahead of the move is the clue. Traders who track statements from Japanese finance officials often get a warning, and many reduce size or step aside once the language changes.

Interventions also tend to produce temporary relief, followed by a return toward the old trend if the underlying drivers are unchanged.

Has anyone dealt with an intervention spike, and what did it cost or earn?