天地無用

Short from 天地(てんち) (tenchi, “top and bottom”) + 入替(いれかえ) (irekae, “replace, swap”) + 無用(むよう) (muyō, “prohibited”), i.e. "swapping top and bottom is prohibited."

• (Tokyo) て​んちむよー [téꜜǹchì mùyòò] (Atamadaka – [1])[1]
• IPA^(key): [tẽ̞ɲ̟t͡ɕi mɯ̟ᵝjo̞ː]

天(てん)地(ち)無(む)用(よう) • (tenchi muyō) 

1. (dated) Shipping terminology to indicate that a package must not be flipped: this way up, this side up

• This phrase is sometimes misinterpreted as "top and bottom do not matter", using the more readily comprehensible interpretation of 無用 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 この面(めん)を上(うえ)に (kono men o ue ni, “this side up”) and 逆(さか)さま厳禁(げんきん) (sakasama genkin, “upside down prohibition”).

• 割(わ)れ物注意(ものちゅうい) (waremono chūi, “caution fragile”)

• http://www.bunka.go.jp/prmagazine/rensai/kotoba/kotoba_008.html