Kolin Burges, a self-styled cryptocurrency trader and former software engineer from London, holds a placard to protest against Mt Gox, in front of the building where the digital marketplace operator was formerly housed in Tokyo on February 26. Japanese authorities are looking into the abrupt closure of Mt Gox, the top government spokesman said on Wednesday in Tokyo's first official reaction to the turmoil at what was the world's biggest exchange for bitcoin virtual currency. Reuters/Toru Hanai