Japan's Finance Minister, Shun'ichi Suzuki, has stated that they will respond appropriately to sharp FX moves and that they are closely watching FX moves with a high sense of urgency. He did not comment on levels, however.
    
He said that fx intervention has yielded certain effects and they cannot tolerate excess FX volatility in speculative trading.

Japan's recent currency intervention has yielded "certain effects", Suzuki said after the government spent a record amount supporting the yen last month.

Meanwhile, the yen fell to 148.80 vs. the greenback at the start of this week and was under pressure following a dovish Bank of Japan kept ultra-low interest rates, bucking the trend among other major central banks.

BOJ Governor Haruhiko Kuroda said the central bank was nowhere near raising interest rates, with inflation in Japan likely to fall short of its 2% target for years to come.

USD/JPY H1 chart