Currency intervention is costly and could fail to influence the yen's value in the huge global foreign exchange market. Analysts say Japan may face difficulty winning backing for intervention unless volatility becomes highly excessive. Investors see solo action by Japan being far less effective than concerted intervention. Last month, Japanese authorities sold dollars and bought yen in a market intervention for the first time since 1998, spending 2.8 trillion yen ($19.2 billion) to slow a rapid slide in the yen that was considered a threat to the economy. read moreAs for dollar-buying, yen-selling intervention, Japan has stayed out of the market since 2011 when the devastating earthquake and tsunami triggered the worst nuclear disaster in Fukushima since Chernobyl.

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