A government-led campaign to persuade office workers to dress lightly in the summer months from June to September is now underway. The name of the campaign, Cool Biz, comes from the English words cool and business. Research suggests that the temperature feels two degrees lower to men who do not wear neckties, and the campaign seeks to exploit this to save energy and prevent global warming by keeping the air conditioning in offices at 28 degrees Celsius.

Prime Minister Koizumi Junichiro expressed his support for the Cool Biz campaign by wearing a light and airy kariyushi shirt from Okinawa Prefecture, where the summer sun is fiercely hot, while Nippon Keidanren (Japan Business Federation) Chairman Okuda Hiroshi modeled the Cool Biz look at EXPO 2005, Aichi, Japan.

Department stores say that demand for Cool Biz-related products is booming. Some outlets report that sales of shirts with high, button-down collars, which look good even without a tie, are up 60% on last year. Other products selling well include slacks, which go well with these shirts; belts, which in the absence of jackets are now visible more often; and V-neck undershirts, which cannot be seen under shirt collars.

Koike Yuriko expressed the government's determination to further promote Cool Biz, saying, "We want to change businessmen's fashion so that Cool Biz becomes second nature."