Japanese high-tech firm Hitachi on Wednesday revised its half-year net profit forecast five times higher, citing a smooth recovery from the March earthquake and tsunami. Hitachi now estimates its net profit for the six months to September at 50 billion yen ($658 million), up from a previous forecast of 10 billion yen. The company also raised its projection of operating profit to 170 billion yen from 100 billion yen and sales to 4.55 trillion yen from 4.40 trillion. The upbeat revision boosted shares in Hitachi on the Tokyo Stock Exchange, despite a stronger yen threatening the repatriated profits of exporting firms. Hitachi gained 3.66 percent to 424 yen, outperforming a declining Nikkei index. Like many other Japanese firms, Hitachi -- whose products range from microchips to nuclear power equipment -- reported damage to its production facilities and electricity supply problems after the March 11 disaster. Hitachi said the earnings recovery was robust in such segments as telecommunications systems, social and industrial infrastructure and automotive systems. Besides the higher-than-expected revenue, cost cuts contributed to the higher projections despite a negative impact from the yen\'s rapid appreciation, it said. Hitachi left unchanged its full-year forecast, citing \"extreme uncertainty\" over the global economy, the impact of flooding in Thailand on operations there, currency rates and changes in raw material prices. It will release its April-September earnings results next Tuesday. However, the upgraded half-year profit forecasts are a far cry from results the same time a year earlier when Hitachi reported 158 billion yen in net profit and 218 billion yen in operating profit on sales of 4.5 trillion yen. Hitachi expects a net profit of 200 billion yen in the full year to March 2012 compared to a record 238.87 billion yen last year.