The YEN is back below 80 against the US Dollar. 

On March 17th we had the YEN upside flash crash where the price went from 79.60 to 76.39 in a matter of minutes.

At which point a coordinated G7 intervention took place at the request of the BOJ Governor the following day, March 18th, sending the price back up to 81.9.  

Statement by the BOJ Governor on March 18th:

The Bank of Japan strongly expects that Japan's concerted action with G7 member countries in the foreign exchange market will contribute to the stable formation of foreign exchange rates.  The Bank of Japan will pursue powerful monetary easing and, to ensure stability in financial markets, will continue to provide ample liquidity. 

The USD/JPY price did stabilize after the coordination and reached a high of 85.5 before falling to pre YEN upside flash crash level today, 79.7.

Will central banks intervene again?

The IMF's acting head, John Lipsky, warned in a press conference that the G-7 countries are prepared to intervene again if it's warranted, given the success of the most recent intervention, in March.

However, I'm not sure how much of a success it was considering we are back to the same levels two and a half months later.

It's clear that the G-7 at least is willing to take action in the case of market conditions that appear to be disorderly, Lipsky said.

According to Marc Chandler, chief currency strategist at Brown Brothers Harriman, the move in yen-dollar is a result of dollar weakness rather than undue yen strength.  He spoke to CNBC on the odds of an intervention right now, Two chances: slim and none, and slim just left town.