In Japan its the Ministry of Finance that orders (or not) currency intervention.
Japan’s Finance Ministry’s Vice Finance Minister for International Affairs is the guy (its normally a guy, yeah) who will instruct the BOJ to intervene, when he judges it necessary. Often referred to as Japan’s ‘top currency diplomat’.
Anyway, at the moment its Masatsugu Asakawa:
Who has just been nominated as next head of Asian Development Bank.
But, get this … the current head of the ADB is Takehiko Nakao, who was a previous ‘top currency diplomat’.