It is a bright, sunshiny day in Musashino Central Park in Tokyo's Musashino City, but the wind is a little strong for the participants in the Japan Paper Airplane Association semifinal flyoffs.
"The wind is a problem today," says Tamotsu Kuroda, recording secretary for the meet. The contestants, wearing numbered cards on their backs, are slinging their craft into the sky, but again and again the sudden, unpredictable gusts put them into premature nosedives. The flight times are low.
"Duration is how it's scored," explains Kuroda. "Altitude doesn't matter."