One way to spend the government's cash handout this three-day weekend is to dine out — and in the process donate clean water to African children to celebrate World Water Day.

The Tap Tokyo campaign, backed by UNICEF, will run at more than 200 cafes and restaurants in Tokyo and Kanagawa, Saitama and Chiba prefectures from Friday to Sunday. Customers will be invited to give ¥100 or more in return for complementary water or tea.

"A mere ¥100 can provide clean and safe water for a child for 40 days," said a spokeswoman for the Japan Committee for UNICEF, which is supporting the project organized by advertising agency Hakuhodo Inc.

The UNICEF-backed Tap Project, which marks World Water Day this Sunday, raised $100,000 when it was launched in New York in 2007. It spread to other U.S. states, Canada and New Zealand the following year. In its Asian debut in Japan this year, the organizers are aiming to collect ¥10 million to match New York's efforts in the inaugural year.

Participating restaurants range from the long-established Western restaurant Matsumotoro in Hibiya Park, Chiyoda Ward, to Wired Cafe, a chain of Internet cafes.

Although more than half the time allotted has passed since the U.N. declared its Millennium Development Goal of halving the number of people without access to safe water by 2015, Madagascar is still nowhere near the target, according to the UNICEF spokeswoman.

"Only 47 percent of the country has access to clean water, and standards have fallen since the target was set," she said.