Drawbridge
There are three drawbridges in NetHack - one in the Castle, and the other two on the Valkyrie quest. They are widely considered extremely dangerous; however, their threat can easily be managed by a knowledgeable player. Indeed, with a little caution the drawbridge can be a valuable tool.
A closed drawbridge is represented by #, and an open one is represented by ..
Contents
Opening and Closing
The castle drawbridge is opened by playing the passtune on a musical instrument. The passtune can be given to you by your god while praying on an altar, or deduced by playing a game of musical mastermind in front of the drawbridge (gears = right note, right position; tumblers = right note, wrong position). Obviously, Options#sound must be enabled.
Strangely, manipulating the drawbridge in this way does not advance the turn-counter.
The drawbridge can also be opened by wand or spell of opening and by the blessed Bell of Opening.
The drawbridge can also be closed by a wand or spell of locking.
When a drawbridge closes, monsters (or the player) standing on it or the square it closes onto (the portcullis) will be crushed and killed. Phasing monsters always survive. Flying or levitating victims have a chance to survive, significantly lessened if on the portcullis[1] -- just keep trying. When a drawbridge opens, the same applies to monster caught under it.
Destruction
If a drawbridge (open or closed) is hit by a force bolt (from the spell or a wand of striking) then it is destroyed. Any non-phasing monster in either the "open" square or the "closed" square (the portcullis or the moat) is very likely to die. Drawbridge death is irrespective of hit points or armor class. However, those flying or levitating have a greater chance of survival.
Note that it is only those two squares that are at risk. It is a myth that you can be hit with flying metal at a greater range[3][4].
Once destroyed, a drawbridge can never be recreated. Casting a spell of wizard lock or the equivalent wand at the portcullis square creates an ordinary door.
Strategy
Once you have the passtune the drawbridge can be opened and closed instantly and at will by playing the instrument again. Anything standing on the moat or portcullis squares will be killed (and you will even gain experience for the kill). If a flying monster survives you can just try again, taking zero game time. This is a fairly safe way of clearing out the hordes of monsters in the castle courtyard. Do note however that this will destroy any possessions carried by the monsters you crush.
If you stand in a line with the drawbridge and the castle fountain then soldiers inside may try and zap you with wands of striking, inadvertently destroying the drawbridge. For this reason you should stand a knight's move away from the drawbridge when using it to crush the inhabitants.
Exercise caution when crossing the drawbridge. You never know when a monster with a wand of striking may be lurking. Some players prefer to destroy the bridge when they're done crushing things. Alternatively, jumping (other than the Knight's innate L-jump) can take you through the danger zone in a single move, leaving no time for monsters to destroy the drawbridge under you.
The drawbridges in the Valkyrie quest
The drawbridges in the Valkyrie quest cannot be opened or closed with the passtune. Other methods still work: a wand of locking or wizard lock spell will close them, while a wand of opening, knock spell, or the Bell of Opening will open them. They are subject to being destroyed by force bolt or a wand of striking, with the same risk of instadeath as the Castle drawbridge.
Fort Ludios
The door beyond the moat of Fort Ludios is not a drawbridge, but an ordinary door.
Reference
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.
