Was at a comrades place yesterday who is currently studying a most interesting subject - Japanese school girls ^^;
He had these up on his wall - posters which are being used in the Niigata prefecture to help discourage school girls from rolling up their skirts.
The pink poster says "By putting in more effort, you will do well for both study and (extending) your skirt length."
Folks who run schools are generally not happy about the short skirts and want them extended to default length.
The reasons they give are things like the girls getting ill from catching a cold (from wearing short skirts) and because of some incidents where some girls had their skirts cut by perverts.
The skirt on right is a standard skirt but the one he left has been developed to stop the girls from rolling up their skirts by making the whole skirt messy after a rollup attempt.