# Blindness
Blindness is a property that appears in NetHack. Blindness occurs when your sight is impaired and blocked, which renders you unable to see most things on a level and omits any and all messages related to actions that you would otherwise see.
The zen conduct consists of playing the entire game blinded.

Contents

1 Description

1.1 Object appearances
1.2 Monsters

2 Sources
3 Internals

3.1 Blinded

3.1.1 Creamed

3.2 Blind

4 Strategy

4.1 Curing blindness
4.2 Resisting blindness
4.3 Navigating while blind
4.4 Discovering objects

5 Messages
6 References

Description
When moving normally while blind, using near look via : or picking up items via ,, you will automatically use your hands to feel for items on the ground. Moving onto a seemingly empty square with a monster on it will cost you a move (without attacking), show the monster as I and anger it if peaceful, even while safe-moving via m.[1] Moving into a square with an I or warning symbol will cause you to attack that square - safe-moving via m will function as normal if a monster is occupying the square, or move into the square normally if it is empty.
If you possess intrinsic or extrinsic telepathy while blind, all non-mindless monsters on the level are displayed - interactions with these monsters are handled normally, both for normal movement and safe-moving via m. Monster detection granted via a blessed potion or casting of the spell at Skilled lets you see all monsters on the level even while blind, and they are also handled normally for purposes of movement. The Eyes of the Overworld will not prevent blinding, but the astral vision conferred by wearing them will allow you to see while blind, and therefore breaks zen conduct. Warning also functions as normal, as it does not rely on you being able to see the monsters in question.
Messages describing actions such as monster-versus-monster-combat that you cannot see are omitted, and gaze attacks will have no effect on you while blind.

Object appearances
While blind, most unidentified objects will show up only as their object class (e.g. "a potion", "a ring", "a long sword" etc.), including artifacts - only amulets and food are treated as "seen" while blind. Poisoning and erosion status of weapons are still shown; erodeproofing and charges are only shown if formally identified (even if you erodeproofed it yourself while blind). Any dilution in potions is only displayed if you know that potion's appearance. While blind, you cannot class-name unidentified objects, and any individual names will not be displayed (but will affect stacking and artifact naming).
Other objects that you will always know the appearance of are:

Eggs laid by you.[2]
The appearance of your starting inventory and that of your pet.[3][4]
You can "hear" the appearance of a scroll if a monster reads the label, though it will not auto-identify since you will not be able to see the result of most scrolls. The same is true for potions - you can still hear them being quaffed, but cannot see the result. Polymorphing any object and alchemizing or fully diluting potions will render it unseen.
As most sources of blindness are generally temporary, you will learn the appearance of any unidentified object you picked up upon the blindness wearing off. However, there are inevitably cases where a cure is not immediately available for long-term blinding, and zen conduct in particular makes it vital to learn how to work around this.

Monsters
Blindness works somewhat differently for you than it does for other monsters in the game - a blind monster will move and attack erratically, and suffers a to-hit penalty. Blinded monsters do not respect Elbereth if they would have normally, and cannot use any gaze attacks they possess.

Sources
Blindness can occur through various methods:

A quaffed, wielded or thrown potion of blindness
A ray of lightning, e.g. from a wand or the breath of a blue dragon
Engraving with a wand of lightning
Breaking a wand of light
The flash of an expensive camera
A thrown, wielded or applied cream pie
Polymorphing into a monster with no eyes.
Being hit by any blinding attack, such as blinding venom, the blast of a yellow light or the melee attack of a raven
Being hit by the blind or lightning monster spells[5]
One of the many effects of a magic trap, which will also deafen you
Sitting on a throne
Wearing a blindfold or towel
Applying a cursed towel with 50% chance
Applying a cursed unicorn horn[6]
Eating food that turns out to be rotten with a 3/16 chance, unless you are already blind[7]
Reading a cursed or difficult spellbook
Walking inside a poison cloud[8]
Internals
In the game's code, three forms of blindness are recognized:

Blinded
"Blinded"[9] refers to all forms of blindness that are intrinsic - that is, you would be blind if you were not wearing or wielding anything and polymorphed into a monster form with eyes. The game records the number of turns you are blinded.

Creamed
Being "creamed" is the result of a substance over your eyes physically restricting your vision.[10] The game also records the number of turns you are creamed. It is a subset of being "blinded", and stacks with blindness - items causing or curing creaming increment the number of turns you creamed and blinded by the same amount, so it is always less than or equal to the number of turns you are blinded.
"Creamed" status will always time out first - e.g., if you are blinded for 100 turns, and 50 turns later you become creamed for a duration of 20 turns, you will be blinded for a total of 70 more turns; during the first 20 of those turns, you are considered creamed.
"Creaming" actions include:

Being hit by or applying a cream pie
Being hit by blinding venom
Applying a cursed towel
Creaming can be undone if you wipe your face; using a noncursed towel will always remove creaming. With the exception of prayer, which cures both, all other actions and cures affect blindness only if it cures either of the ailments.

Blind
"Blind" means you currently cannot see.[11] You can be "blind" without being "blinded", if your eyes are covered by a blindfold or a towel, or you polymorph into a monster with no eyes. You can be "blinded" without being "blind" if you have astral vision.

Strategy
Curing blindness
In addition to allowing any inflicted blindness to time out, there are many ways to cure blindness. You can cure being "blinded" by doing any of the following:

Apply a non-cursed unicorn horn[12]
Invoke the Staff of Aesculapius
Eat a carrot
Cast a spell of cure blindness or extra healing
Drink a non-cursed potion of healing, any potion of extra healing, or any potion of full healing.
Prayer can cure you of being "blinded", though this form of blindness is considered a minor trouble.
"Creamed" blindness can be cured by using the #wipe command, apply a noncursed towel, or prayer. If you are rendered blind from a worn towel or blindfold and it is not cursed, you can simply remove it - having a cursed blindfold or towel stuck to your face is considered a major problem, and thus a safe prayer is likely to solve it. You can also uncurse them by using a scroll of remove curse, the spell of remove curse, or dipping them in a potion of holy water.
If polymorphed into an eyeless form, you can polymorph to a different form with eyes or return to normal.

Resisting blindness
There are a few items that allow you to resist blindness as well.

While you are wielding Sunsword, you will be protected from light-based sources of blindness.[13][14] This includes yellow lights, magic traps, and wands of lightning.[15][16] [17][18]
Wearing a blindfold or towel can protect from blinding gazes and some other sources, such as blinding attacks - it will not prevent blindness from quaffed or thrown potions, however.
Astral vision granted from The Eyes of the Overworld does not cure or resist blindness, but allows you to see despite it.
Navigating while blind
Moving normally while blind means you may bump into or even attack unseen monsters - you could inadvertently kill your pet or anger a shopkeeper, making it incredibly dangerous to do so without telepathy or monster detection. Being blinded in Minetown or other similar areas may get you on the wrong side of the watch as well. Stormbringer in particular is made even more risky to wield than it already is.
Very special care should be taken on levels with cockatrices - if there is a cockatrice corpse on the ground, feeling around for objects while blind may resulting in an instant stoning unless you are wearing gloves. Even worse, if you are blind and warned, moving with m into a cockatrice without wielding anything or wearing gloves will still stone you if the warning symbol does not cover an undisplayed I.
Moving with m followed by a direction allows you to ignore items on the ground and avoid attacking monsters, though you will still angers any peacefuls you bump into if you could not see them. A stethoscope can be applied for free once per turn to determine if something is in your path and it is unsafe to move there. Allowing unseen hostile monsters to attack you first is risky, even if you attack the specific square you were hit from - some may be fast enough to move away after attacking, resulting in a wasted turn attacking the I where they previously were. Nearby peacefuls and pets add to the danger, since you cannot see if they stepped into any square previously occupied by a hostile (or worse, killed the hostile themselves in the pet's case). In rare cases, #chatting is useful to test for non-silent monsters since it does not use a turn if you get no answer.
Telepathy and warning are the best properties to have in case you are blinded, since warning complements telepathy by revealing the positions of most mindless monsters - while even these properties combined will not reveal all possible monsters, the few mindless monsters not revealed by warning are generally not a threat at most points where you have access to both. (Further corner cases stem from hiders, mimics, Stormbringer, F, and deactivating safe_pet.)

Discovering objects
You can make an object "seen" and gain knowledge of its appearance and type via formal identification, as well as through various other methods.
A blessed potion of object detection reveals the appearance of all objects on the current dungeon level, recursively including the contents of containers.[19] A wand of probing will grant non-recursive knowledge of any objects it is zapped at, including the contents of containers and the inventory of any monsters in its path; you can also zap it at yourself in order to see your inventory.[20][21][22]
You can dip items in holy/unholy water when blind, allowing you to learn their beatitude. Buying or selling something at a shop will have the shopkeeper identify its appearance for you, with the exception of items in containers, stolen merchandise, or items covered by your credit when you teleport out.[23]
Your quest leader will identify your own quest artifact and the real Amulet of Yendor for you.[24][25] Additionally, the crowning gift you would receive if neutral or chaotic is made "seen" if you are already holding it. The special attacks of the Tsurugi of Muramasa and Vorpal Blade will always reveal their appearance upon activating.[26][27][28][29].
Other methods of object identification include:

Eating one of a stack of tins will make the remaining ones known.
Astral vision allows you to see objects while blinded - but remember that this will break zen conduct.
Messages
Pardon me, 

<foo>.
You moved with m into a pet either displayed as I or properly seen.[30]
You move right into [<foo>.
You moved with m into a non-tame monster that was either either displayed as I or properly seen.[31]
Wait! There's something there you can't see!
You moved onto a seemingly empty square. This does not attack whatever was on that square, but does anger them if they were peaceful.
References

↑ src/uhitm.c in NetHack 3.6.0, line 137

↑ src/sit.c in NetHack 3.6.0, line 305

↑ src/u_init.c in NetHack 3.6.0, line 1074

↑ src/dog.c in NetHack 3.6.0, line 193

↑ src/mcastu.c in NetHack 3.6.0, line 559

↑ src/apply.c in NetHack 3.6.1, line 1885

↑ src/eat.c in NetHack 3.6.6, line 1547

↑ src/region.c in NetHack 3.6.0, line 929

↑ include/youprop.h in NetHack 3.6.0, line 85

↑ include/you.h in NetHack 3.6.0, line 320

↑ include/youprop.h in NetHack 3.6.0, line 88

↑ src/apply.c in NetHack 3.6.1, line 1997

↑ src/mondata.c in NetHack 3.6.0, line 153

↑ include/artilist.h in NetHack 3.6.0, line 153

↑ src/mhitu.c in NetHack 3.6.0, line 1929

↑ src/trap.c in NetHack 3.6.0, line 3051

↑ src/zap.c in NetHack 3.6.0, line 2157

↑ src/zap.c in NetHack 3.6.0, line 3978

↑ object_detect in detect.c in NetHack 3.6.0

↑ src/zap.c in NetHack 3.6.0, line 434

↑ src/zap.c in NetHack 3.6.0, line 1811

↑ src/zap.c in NetHack 3.6.0, line 2369

↑ src/shk.c in NetHack 3.6.0, line 2323

↑ src/quest.c in NetHack 3.6.0, line 213

↑ src/quest.c in NetHack 3.6.0, line 227

↑ src/artifact.c in NetHack 3.6.0, line 1261

↑ src/artifact.c in NetHack 3.6.0, line 1278

↑ src/artifact.c in NetHack 3.6.0, line 1308

↑ src/artifact.c in NetHack 3.6.0, line 1324

↑ src/hack.c in NetHack 3.6.0, line 1409

↑ src/hack.c in NetHack 3.6.0, line 1411

This page may need to be updated for the current version of NetHack.
It may contain text specific to NetHack 3.6.1. Information on this page may be out of date.
Editors: After reviewing this page and making necessary edits, please change the {{nethack-361}} tag to the current version's tag or {{noversion}} as appropriate.

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