# Secret passage
Secret passages or hidden corridors, represented by &nbsp;, are a type of terrain that appear to be solid rock until exposed, when they turn to an ordinary corridor.
When a room and corridor level is generated, secret passages are often created on some corridor squares.  You can sometimes guess the existance of a secret passage from surrounding corridor squares, especially if they are at a corner, but corridors can also have natural dead ends.
Until exposed, a secret passage doesn't only look like solid wall, but also acts like one: monsters (including pets) won't step on a secret passage square, the square blocks thrown objects, and you can't see through them.  

Exposing a secret passage
There are multiple ways to expose a secret passage, turning it to an ordinary corridor square.

The search command or the automatic searching property has a chance of finding them: see searching for what influences the probability.
Apply a stethoscope at them.
Read a blessed scroll of magic mapping.
Cast the spell of detect unseen or zap the wand of secret door detection when you're near the corridor.
Start to dig the secret door square.
Kicking can expose them sometimes.
Secret passages are more difficult to expose than secret doors, as effects that would usually open or break down a door (multiple wands or spells) do not work on them.

This page may need to be updated for the current version of NetHack.
It may contain text specific to NetHack 3.4.3. Information on this page may be out of date.
Editors: After reviewing this page and making necessary edits, please change the {{nethack-343}} tag to the current version's tag or {{noversion}} as appropriate.