The Principal's Key (校長室の鍵 Kōchōshitsu no Kagi , lit. "Principal's Office Key) is an item found in Corpse Party.
The principal's key can be found after reading through Yoshie Shinozaki's diary. In the walkway leading to the annex, the principal can be seen falling from the rooftop in an endless loop. Satoshi Mochida spots the key on his body and proceeds to retrieve it. It is noticeably small for a door key and a small charm is tied to it.
It is used to get into the principal's office in the second wing.