AlQa'dah 12, 1433, Sep 28, 2012, SPA -- Japan's unemployment rate edged down to 4.2 per cent in August, the lowest in 11 months, dpa cited the government as saying Friday. The number of unemployed decreased by 180,000 in August from a year earlier to 2.77 million, in the 27th consecutive month of decline, the ministry said.