If there were a contest for the best currency trade of the past three months, the weakening yen would get a blue ribbon.
The decline in the yen against the dollar and the euro has been nothing short of stunning, and major investors have reaped billions in profits on selling the Japanese currency.
Interestingly, the move, which has been driven by political change and jawboning, has been far more effective than multiple attempts by the Bank of Japan to intervene and curb the yen's strength.
Whether the yen can keep falling, though, is another question.
Italy's shocking preliminary election results sent the yen sharply higher as investors moved out of the euro and other riskier currencies. And while a move of that speed is hardly likely to be repeated, it could be pointing to a certain kind of shift.
"The speed of the swan dive in the Yen crosses suggests that a major hedge fund could have been unwinding its short Yen position," wrote Kathy Lien, a managing director at BK Asset Management, wrote in a note to clients. "It wouldn't be a complete surprise if some funds decided to liquidate."
That said, Lien thinks the yen still has further to fall. There are strong rumors that the Bank of Japan is about to get a dovish new chief, and Lien thinks official comments when the new central banker is named could send the dollar-yen pair above 95.
Similarly, the strategists at Barclays Capital are edgy about the sudden reversal of the yen's slide, noting that a deterioration in market sentiment sideswiped a dollar-yen rally in 2012 - but they believe the latest yen move higher is overdone, and they see it as an opportunity to buy the dollar against the yen.
Jens Nordvig, global head of currency research at Nomura Securities, has a rather different view.
"The yen trade really could be over," he told me. "It has been a sustained trend, for 3-4 months, without a major setback," he adds, alluding to the December election of the stimulus-minded Shinzo Abe as prime minister and the current rumors about the possible new head of the Bank of Japan. "Now we have the right guy named as BOJ candidate, and we see USDJPY sharply lower."
Nordvig says his models suggest the yen is currently trading fairly close to fair value.