The war in the Middle East has raised energy costs and prompted Tokyo's leadership to update the "Cool biz" strategy - a previous initiative to avoid using air conditioning as much.
In 2005, employees were urged to skip the jacket and tie to stay cool. This summer, early mornings and shorts are the order of the day, according to Tokyo Governor Yuriko Koike.
"This summer, we encourage cool clothing that prioritizes comfort," she said, giving examples of polo shirts, t-shirts, sneakers and - depending on the work tasks - shorts.
Koike said the war in the Middle East has made electricity more expensive.
