Digital currency destabilizing effect on the Chinese Yuan currency due to speculation. Recent interest in cryptocurrencies has prompted renewed interest in digital currencies, with bitcoin, introduced in 2008, becoming the most widely used and accepted digital currency. According to the European Central Bank's 2015 "Virtual currency schemes – a further analysis" report, virtual currency is a digital representation of value, not issued by a central bank, credit institution or e-money institution, which, in some circumstances, can be used as an alternative to money. In the previous report of October 2012, the virtual currency was defined as a type of unregulated, digital money,
Currency War of 2009–11 the rise in the Euro in the latter half of 2010 was China's purchase of Euro-denominated bonds. While China's intervention was in some ways helpful for the Eurozone, it also generated concern with several European officials speaking out against the action. These officials included: ECB governor Jean-Claude Trichet and Eurogroup president Jean-Claude Juncker. 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