Spells (learning, practising, and casting) in NetHack 3.4

spl1-343.html Last edited 2004-05-29 for NetHack 3.4.3
Compiled for 3.2.2 by Kevin Hugo.
Updated for 3.4.3 by Dylan O'Donnell <psmith@spod-central.org>.
Converted to HTML by Kate Nepveu <knepveu@steelypips.org>; HTML re-synchronized 2005-08-29 by Dan Fabulich.


Editor's note: Spell effects are in the second half of the spell spoiler, spl2-343.html. You can also follow the links in the table below to go directly to that spell's effects in the other file.

blank paper $0 50 18 0 0 0   plain
Book of the Dead 10000 20 0 7 0 0   papyrus
force bolt 100 50 35 1 2 10    
drain life 200 50 10 2 2 20    
magic missile 200 50 45 2 2 20 Wiz  
cone of cold 400 50 10 4 21 40 Val  
fireball 400 50 20 4 12 40    
finger of death 700 50 5 7 80 70    
healing 100 50 40 1 2 10 +  
cure blindness 200 50 25 2 2 20 +  
cure sickness 300 50 32 3 6 30 Hea+  
extra healing 300 50 27 3 10 30 +  
stone to flesh 300 50 15 3 2 30    
restore ability 400 50 25 4 15 40 Mon+  
detect monsters 100 50 43 1 1 10    
light 100 50 45 1 1 10    
detect food 200 50 30 2 3 20    
clairvoyance 300 50 15 3 6 30 Sam  
detect unseen 300 50 20 3 8 30    
identify 300 50 20 3 12 30    
detect treasure 400 50 20 4 15 40 Rog  
magic mapping 500 50 18 5 35 50 Arc  
sleep 100 50 50 1 1 10    
confuse monster 200 50 30 2 2 20    
slow monster 200 50 30 2 2 20    
cause fear 300 50 25 3 6 30    
charm monster 300 50 20 3 6 30 Tou  
protection 100 50 18 1 3 10    
create monster 200 50 35 2 3 20    
remove curse 300 50 25 3 10 30 Pri+  
create familiar 600 50 10 6 42 60    
turn undead 600 50 16 6 48 60 Kni  
jumping 100 50 20 1 3 10    
haste self 300 50 33 3 8 30 Bar  
invisibility 400 50 25 4 15 40 Ran  
levitation 400 50 20 4 12 40    
teleport away 600 50 15 6 36 60    
knock 100 50 35 1 1 10    
wizard lock 200 50 30 2 3 20    
dig 500 50 20 5 30 50 Cav  
polymorph 600 50 10 6 48 60    
cancellation 700 50 15 7 64 70    

Spellbooks are listed above by school, then increasing level. The COST field denotes the base price of each item. WGT specifies the weight (100 zorkmids weighs 1).

Spellbooks comprise 4% of all randomly-generated items in the main dungeon, 12% in containers, 0% on the Rogue level, and 0% in hell. PROB is the relative probability of each subtype. They appear 1/34 cursed, 16/17 uncursed, and 1/34 blessed. There is also a chance of obtaining a spellbook (if possible, one you haven't learnt yet and whose school you're unrestricted in) from praying when your god is pleased. A Wizard will usually receive a blessed spellbook of finger of death when crowned; a Monk, a blessed spellbook of restore ability.

The level (LVL) of a spell controls how difficult it is to cast and how much energy is required. Normal spellbooks cost 100 times their level. READ indicates the number of turns needed to successfully read a particular spellbook.

MRKR specifies the maximum number of magic marker charges needed to write a spellbook of that type, or zero if it cannot be written. You may note that this number is 10 times the spell level. The actual number of charges used will be a random amount from MRKR/2 to MRKR-1. Wizards have a base 1/3 chance of writing an unknown book, and all other classes have a base 1/15 chance; your chance generally improves with higher luck, to a maximum of about 98% for Wizards and 32% for other classes. You can only write on spellbooks of blank paper, which can be made by getting any spellbook wet, cancelling any spellbook (except spellbooks of cancellation), or reading a spellbook until it is too faint to be read anymore. The Book of the Dead can't be blanked by any means. You can select non-blank spellbooks to write on, but this will abuse your wisdom and you will be told, "That spellbook is not blank!"

Some spells provide a BONUS against spell failure. Each character class has a particular spell that they are good at casting (noted with class identifier). In addition, the spells marked with a plus (+) are emergency spells that grant an additional bonus. See the section on calculating spell failure below for details. Note that this column does NOT list which spellbooks a character may start with.

Some types of spellbooks have the same APPEARANCE when unidentified. The appearance of the remaining spellbooks are are randomized from the following descriptions:

Reading spellbooks

Each spellbook takes a certain number of turns to READ it, noted above. (Wearing lenses will reduce this number by, on average, one-third.) If the spellbook is cursed, you will fail to learn the spell, will be paralyzed for the given number of turns, and will be subject to a bad effect (chosen randomly, with worse effects only being able to be caused by higher-level spells):

There is a 1/3 chance that the book then crumbles to dust.

If the spellbook is uncursed, there is a random chance of the same effects happening as for a cursed spellbook, depending on your INTelligence, your experience level (XL),and the spellbook's level (LVL):

1 - ((INT + 4 +(XL/2) - (2 * LVL)) / 20)

(If you are wearing lenses, the factor of 4 is increased to 6.)

Wizards will be warned if this chance is non-zero and given the option to abort the reading attempt.

Blessed spellbooks never cause these bad effects.

You will never learn a spellbook while confused, and attempting while you are has a 1/3 chance of destroying the spellbook (except the Book of the Dead).

"Being confused you have difficulties in controlling your actions. You accidentally tear the spellbook to pieces." (book destroyed).
"You find yourself reading the <next/first> line over and over again." (book not destroyed)

If you are interrupted while reading, you may continue your efforts by reading the same spellbook again.

When you successfully read a spellbook, there are four outcomes. If you do not yet know the spell, "You add the <spell> to your repertoire", ("You learn the <spell>" if the first spell you have learnt), identify the spellbook, get 20000 turns use of the spell, and increment the number of times you've studied that particular spellbook. For spells already known, if the book has been studied more than 3 times "This spellbook is too faint to be read anymore" and the spellbook turns into blank paper. Otherwise, if you had 1000 or fewer turns use of the spell remaining, then "Your knowledge of the <spell> is keener", you have 20000 turns' use of the spell again, you exercise your wisdom, and the number of times you've studied that particular spellbook is incremented. But if "You know the <spell> quite well already", then there is no further effect and the number of times you've read the spellbook is unchanged.

Reading a spellbook will give you 20000 turns during which that spell can be used freely. If you use the spell towards the end of this time, you will get warning messages:

1001 to 20000 turns left No message.
101 to 1000 turns left "Your knowledge of this spell is growing faint."
1 to 100 turns left "You strain to recall the spell."

Expiry of this time is denoted by an asterisk (*) next to the level in the spell's listing. If you try to cast an expired spell, "Your knowledge of this spell is twisted" and you will become stunned and/or confused for a number of turns depending on the spell's level (LVL):

40% 3 * (LVL+1) 0
30% 2 * (LVL+1) (LVL+1)
20% (LVL+1) 2 * (LVL+1)
10% 0 3 * (LVL+1)

You may reset the time left to 20000 turns by rereading the spellbook after the usage time has been reduced to 1000 turns.

Reading the Book of the Dead has immediate effect. If you are standing on the vibrating square with a lit Candelabrum of Invocation with its quota of seven candles, and have rung the Bell of Opening there within the last four turns, and all three items are uncursed, then the staircase to Moloch's Sanctum is opened. Otherwise, the invocation fails, and a message is given to suggest why this may be the case. Outside of an invocation situation, if the Book is blessed you will tame nearby co-aligned undead, and render any other undead in sight peaceful and cause them to flee; if it is uncursed, there is no effect beyond a random message; if it is cursed, some undead will be summoned, corpses in your inventory revived and eggs in your inventory rejuvenated.

Spell skills

Since the integration of the "wizard patch" into NetHack 3.3, characters have had individual skill levels associated with particular groups of spells, in a manner analogous to the weapon skills. As with weapons, continued use of a spell gives you practice in its spell school. With enough practice in a school of magic and experience levels, you may have the opportunity to advance your skill level in that school. This will in turn lead to reduced failure rates and an improvement in effects caused by spells in that school.

There are specifically two requirements needed to advance a spell school: a number of successful castings of any spell in the school and a number of experience levels. Castings to a total of 20 are needed to achieve basic level, 80 to become skilled, and 180 to become expert, with each spell cast contributing a number equal to its level to this total. These are cumulative from the beginning of the game (though if you start out at basic level in a school you are precredited with the 20 castings that would have been needed to achieve it).

The other criterion used to advance skill levels is experience levels. Each time you gain an experience level, you earn a "skill slot" that is used up when you an advance a skill. Thus you can earn a maximum of 29 skill slots, by advancing from level 1 to level 30. If you lose an experience level, you lose the associated skill slot; if that skill slot was used to enhance a skill, you will lose the most recently earned skill and are refunded the remaining skill slots from that skill level. Going from unskilled to basic or basic to skilled costs one slot; going from skilled to expert costs two slots. Note that these slots are shared with weapon skills.

When you start the game, Healers and Monks will have basic skill in the healing school, Priests in clerical and Wizards in attack and enchantment; you will be unskilled in all other schools. When you reach the point when you can advance a skill category, you will see the message, "You feel more confident in your spell casting skills." You can then advance the skill using the #enhance command (alt-e on some systems). You may choose to not advance a skill level if you want to reserve the skill slots for a different school or weapon class. After advancing a skill, if you are ready to advance another skill (possibly the same one), you will get the message "You feel you could be more dangerous!" The #enhance command can also be used at any time to check your current skill levels.

Different classes can reach different maximum levels in the spell schools, as follows:

School Arc Bar Cav Hea Kni Mon Pri Ran Rog Sam Tou Val Wiz
attack b s b - s b - - - s - b E
healing b - - E s E E b - - - - s
divination E - - - - b E E s - b - E
enchantment - - - - - b - - - - b - s
clerical - - - - s s E - - s - - s
escape - - - - - b - b s - s b E
matter b - s - - b - - s - - - E

The term "restricted" is used to describe schools in which you are permanently unskilled. They do not appear in the #enhance menu, although you will see schools that are unskilled and can be advanced.

Spell failure

There are some preliminary needs that must be met for any spellcasting. The spell must be already known and have been (re)learnt less than 20000 turns ago. You need at least 11 nutrition (weak, near fainting) unless you are casting a spell of detect food. You must have a strength of at least 4, must have a free hand (both can't be welded to weapons and/or a shield), and must not be overtaxed. Finally, each attempt to cast a spell drains energy equal to 5 times the spell's level (randomly up to three times this amount if you have the Amulet) for a successful casting, or half as much for a failure. (See hppw-343.html for details of how fast you will regain this energy.) Your hunger increases by twice the amount of energy that would be drained for a success regardless, but it will not make you faint. For Wizards, this hunger loss is reduced by an amount depending on intelligence; halved for INT of 15, quartered for INT of 16, or eliminated entirely for INT of 17 or greater.

There are three factors that cause spells to fail:

There are seven factors that improve spellcasting success:

To calculate spell failure, you first need to sum together the penalties marked with a number sign (#) below. An increasing total penalty is worse for spellcasting, and is limited to a maximum of 20.

# The "BASE" value from the table below, depending on the character's class.
# If an "emergency" spell (noted with a + above), the "EMERG" field.
# If wearing any shield, the amount in the "SHIELD" field.
# If wearing metallic body armor, the amount in the "SUIT" field.
If also wearing a robe, only add half the amount (rounded down).
# If wearing a robe without metallic armour, *subtract* the amount in the "SUIT" field.
# If wearing a metallic helmet other than the helm of brilliance, add 4. (Metal helmets interfere with the mind.)
# Metallic gloves add 6 (casting channels through the hands).
# Metallic boots add 2 (all metal interferes to some degree).
# Add -4 if the spell is special to that class (see table).
Arc 5# 0# 2# 10# Int Magic mapping
Bar 14# 0# 0# 8# Int Haste self
Cav 12# 0# 1# 8# Int Dig
Hea 3# -3# 2# 10# Wis Cure sickness
Kni 8# -2# 0# 9# Wis Turn undead
Mon 8# -2# 2# 20# Wis Restore ability
Pri 3# -2# 2# 10# Wis Remove curse
Ran 9# 2# 1# 10# Int Invisibility
Rog 8# 0# 1# 9# Int Detect treasure
Sam 10# 0# 0# 8# Int Clairvoyance
Tou 5# 1# 2# 10# Int Charm monster
Val 10# -2# 0# 9# Wis Cone of cold
Wiz 1# 0# 3# 10# Int Magic missile

Next, calculate a base chance of success, which is 5.5 times your intelligence or wisdom STAT, depending on your class. This chance is modified by the following factors:

# SKILL level (unskilled = 0, basic = 1, skilled = 2, expert = 3)
# spell level (LVL)
# experience level (XL)

according to this formula:

difficulty = (LVL * 4) - (SKILL * 6) - (XL/3) - 5

If this is positive, your chance is reduced according to another formula:

chance = base chance - square root of ((900 * difficulty) + 2000)

Otherwise, it will be increased with diminishing returns: the absolute value is multiplied by (15/LVL), capped at 20, and added to the base chance.

The resulting chance is clipped to the range of 0% to 120% success. If you are wearing a shield larger than a small shield, the chance is then reduced to 1/4 its amount (except if it is the special spell for your class -- then it is only halved).

Finally, the chance of success is adjusted by your total penalty using the following formula:

chance = (chance * (20-penalty) / 15) - penalty

The result is clipped to the range of 0% to 100% success.


Thanks to Bruce Cox for proofreading the original version of this file.
Further corrections and clarifications provided by Jason Brown, Snibor Eoj, Monte Mitzelfelt, Petrosky, Pat Rankin, Pekka Rousu, Pekka Savola, Robert R. Schneck, Darshan Shaligram, Jason Short, and Sascha Wostmann.

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