天地無用

Etymology
Short from, i.e. "swapping top and bottom is prohibited."

Phrase

 * : this way up, this side up

Usage notes

 * This phrase is sometimes misinterpreted as "top and bottom do not matter", using the more readily comprehensible interpretation of as meaning "useless" but leading to the exact opposite intended meaning ("it is okay to flip this package"). In Japanese postal services this phrase has been largely replaced by more comprehensible ones like  and.