TOKYO, April 12 (Reuters) - Japan's Nikkei share average edged down but held near five-year highs on Friday, underpinned by ongoing optimism about the economic outlook on the back of bold government and central bank policies. The Nikkei fell 0.5 percent at 13,483.36 after opening a tad higher and hitting a new high of 13,568.25, the highest level since July 2008. Index heavyweight Fast Retailing, which announced its forecasts for the year ending August, dropped more than 3 percent after its weaker-than-expected forecast disappointed the market. It left its full-year operating profit forecast unchanged at 147.5 billion yen ($1.48 billion), slightly lower than analysts' forecast of 149.9 billion yen. The broader Topix shed 0.2 percent to 1,145.13.