Japan also has a large current account surplus , and in 2009 and 2010 the country allowed the Yen to appreciate . However , in September 2010 Japan twice intervened to effect a devaluation . Japan has a number of challenges that limit its ability to allow ongoing currency appreciation , including an aging population , high government debt ( though not net debt as it has high private savings ) and vulnerability to deflation . The September devaluation did not draw widespread international condemnation . Within a couple of weeks upwards pressure on the Yen from the markets had almost entirely undone the effect of the intervention . However shortly after the March 2011 earthquake , other G7 nations joined Japan in a rare act of solidarity , selling billions of Yen to help Japan devalue its currency against pressure from speculators who were betting on a further appreciation , as insurance firms recalled funds from abroad
March 2011 earthquake
2011 Tōhoku earthquake and tsunami
Currency War of 2009–11