June - A drive to save on air conditioning in Japan has boosted sales of casual clothing as businessmen switch to cooler polo shirts and chinos.

Boss Orange collection by Hugo Boss

Japan launched Super Cool Biz last week in an effort to reduce the strain on power supplies in the country after the earthquake and tsunami knocked out key power generation sites.

German menswear retailer Hugo Boss said it had noticed heightened demand for its more casual labels.

"We are currently experiencing growth in Boss Orange and Boss Black Sportswear," a spokesman told Reuters.

Hugo Boss is known mostly for its sharply cut suits but also has several casual brands that sell items such as vintage-looking denim jeans, bohemian-inspired dresses and goat suede bomber jackets.

Japanese businesses are pitching in to keep down energy usage this summer as Tokyo Electric Power Company, which runs the Fukushima Daiichi plant, forecasts tight electricity supply.

Some are shifting workdays to the weekend, when demand will be lower, setting thermostats higher, and keeping lighting to a minimum.

(Reporting by Victoria Bryan; Writing by Maria Sheahan, editing by Paul Casciato)