Hong Kong (CNN Business) A growing number of smaller companies are adopting a four-day workweek. Now the results of a recent trial at Microsoft (MSFT) suggest it could work even for the biggest businesses.

The company introduced a program this summer in Japan called the "Work Life Choice Challenge," which shut down its offices every Friday in August and gave all employees an extra day off each week.

compared to the same period the previous year, the company said in a The results were promising: While the amount of time spent at work was cut dramatically, productivity — measured by sales per employee — went up by almost 40%compared to the same period the previous year, the company said in a statemen t last week.

In addition to reducing working hours, managers urged staff to cut down on the time they spent in meetings and responding to emails.

They suggested that meetings should last no longer than 30 minutes. Employees were also encouraged to cut down on meetings altogether by using an online messaging app (Microsoft's, of course).

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