Traders are piling into fresh bets against the yen, triggering pushback from Japanese authorities who are threatening once again to take action including a possible currency intervention.

The yen edged away from a year-to-date low Wednesday after Masato Kanda, the top currency official at the Finance Ministry, said authorities stand ready to act if needed.

"We’re on standby,” Kanda told reporters, echoing language he used a year ago on the day Japan made the first of three forays into the market. "But I can’t say what we’ll do, and when — we’ll make judgments overall, and we’re making judgments in a state of urgency.”