Every few trading sessions, the yen jolts higher against the dollar, and then it suddenly drops.?

That has become a recurring feature of yen trading in recent weeks, sparking debate among investors and strategists over whether Japanese authorities are trying to stem further weakness in the yen through smaller operations.

On Thursday, the yen jumped as much as 0.5% against the dollar in just two minutes during New York trading before quickly surrendering those gains. A similar move happened on Tuesday, when it abruptly rose by roughly the same amount. On May 8, the yen also briefly climbed 0.2% before reversing course.