Investors are dusting off intervention playbooks once again as a resurgent dollar raises the specter of fresh efforts from officials to protect their currencies.

Taiwan’s central bank issued a rare statement this week to calm investors after global funds slashed their holdings of the island’s stocks and the local currency swooned. A South Korean official told reporters Wednesday the won’s weakness was excessive, while China’s central bank maintained forceful support for its currency with the daily fixing throughout this week.

Speculation is growing that the yen will be next.