Door

Dungeon features
Air	_ Altar
# Corridor	# Cloud
# . Drawbridge	+ - | Door
. Doorway	{ Fountain
| Headstone	.   Floor
> < Ladder	. Ice
# Iron bars	} Lava
} Moat	# Sink
Solid rock	> < Staircase
\ Throne	^ Trap
# Tree	- | Wall

Doors are represented by + when closed, and - or | when open, depending on whether the door is in a vertical or horizontal wall, respectively. Doors are distinct from drawbridges and trap doors.

Opening doors

Doors can be generated locked or unlocked. Unlocked doors are opened using the open command (o). Locked doors can be opened in a variety of ways:

• Unlocking by applying a skeleton key, lock pick, or credit card to the door.
• Zapping a wand of opening at it.
• Casting the knock spell at it.
• Kicking at it until it is smashed to pieces. This should not be done when watchmen or their captains are present, or if a shop is on the other side. (The shopkeeper will be angry that you vandalized his door)
• Zapping a wand of striking or wand of cold at it, destroying it.
• In SLASH'EM, doors can be forced open in the same way chests can.
• Applying an axe, pick-axe or dwarvish mattock on a door will result in the door being smashed to pieces. A shop door will be 'too hard' to chop into.

Doors may be boobie-trapped. Opening them causes 1d(5+level) damage if your dungeon level is less than 5, and 1d(7+level/2) otherwise.

Monsters can unlock locked doors if they are not very small, have hands, and a key (but not other tools). For this reason, you might want to dispose of keys if you lock up the mine town watch. The endgame riders and the Wizard of Yendor can unlock even without a tool. Various giants, titans, and giant zombies can bust locked doors.

Closing doors

Open doors can be closed using the close command (c). Zapping a wand of locking at it will close (and lock) it.

Locking doors

Doors can be locked by applying a skeleton key or a lock pick to a closed door, casting the wizard lock spell, or by using a wand of locking. Some monsters can open closed doors, and amoeboids can ooze beneath locked doors. Shopkeepers can unlock and open doors with a key, and the Riders can unlock doors on the Astral Plane.

Creating doors

A destroyed door, or any square leading to a corridor, can be turned into a fully functional door by zapping the wand of locking or casting the wizard lock spell at it. A destroyed door is not shown on the map, but can be detected with the look command (:).

Finding secret doors

Some walls are in fact secret doors, which can be discovered by searching, brute force, or magic.

Searching is done with the search command (s), and is aided by wearing a ring of searching or wielding Excalibur. Luck affects the chance of a searching successfully, so players who mistreat their luck can find themselves stuck on a dungeon level with no obvious exit. Applying a stethoscope to a wall will tell you if it is a door 100% of the time, with no effect from luck.

The brute force method involves kicking at walls, applying a pick axe, or zapping force bolt at a likely position where a secret door might be. This is very time consuming and often dangerous.

The magical method involves using a wand of secret door detection or the spell of detect unseen and will immediately reveal any secret doors within a 13 square radius.

Messages

You feel an unexpected draft

Whenever a monster breaks a door, there is a one-third chance of this message (affected by verbose option)

Strategy

Using doors in combat

Doors do not allow either monsters or you to pass through diagonally. This can be a great advantage when fighting multiple foes. A door like the entrance to the treasure zoo at the top of sokoban can become a killing ground for monsters who will stream through one by one, allowing you to avoid their ranged attacks.

Using doors to exercise strength

Opening and closing doors exercises the character's strength every time the door resists. This feature can be exploited to enhance the strength attribute. However doors only resist when the player character has very weak strength and low luck.

This technique is only useful for luckless Healers with strength as weak as 7 or 8. With decent physical attributes and luck, the odds of the door resisting become very low. For example, if the character's physical attributes average say 16 with a luck of 4, the chance of the door resisting becomes 1/184 (0.54%). This means that the player has to open/close the door 100 to 200 times to exercise the strength attribute once.

Encyclopedia entry

Through me you pass into the city of woe:
Through me you pass into eternal pain:
Through me among the people lost for aye.
Justice the founder of my fabric mov'd:
To rear me was the task of power divine,
Supremest wisdom, and primeval love.
Before me things create were none, save things
Eternal, and eternal I endure.
All hope abandon ye who enter here.

[ The Inferno, from The Divine Comedy of Dante
                 Alighieri, translated by H.F. Cary ]