Speed

Speed, referred to internally as movement rate, is a form of mechanic in NetHack that governs how often the hero and monsters move relative to each other during a given game turn.

Description

The hero has a base movement rate of 12 points per turn, while each monster has their own base speed that varies depending on the monster type and determines how often they move relative to the hero.

Speed is also calculated somewhat differently for the hero than it is for other monsters: the hero can have their speed augmented by various means (including their starting roles) to become "fast" or even "very fast", while encumbrance can render them slower than they would be otherwise; monsters can be either "fast" or "slow", but are capable of moving and attacking the hero or a monster in the same turn whether via covetous warp or normal movement.

The speed property can make a hero or monster fast, and can be obtained as intrinsic and extrinsic properties.

Player speed

A hero's base speed is adjusted by the following:

• Very fast speed can only be obtained by the hero, and grants a free move (or 12 extra movement points) on ²⁄₃ of the hero's turns, for an average of 5 moves every 3 turns (or an average of 20 movement points per turn). Very fast speed can be obtained extrinsically by wearing speed boots, or as a temporary intrinsic from the potion of speed or the haste self spell.
• Fast speed grants a free move (or 12 extra movement points) on ¹⁄₃ of the hero's turns, for an average of 4 moves every 3 turns (or an average of 16 movement points per turn). Fast speed can be obtained by a hero starting as an Archeologist, Monk, or Samurai, while the Barbarian, Caveman, Knight, and Valkyrie roles gain it at experience level 7; any hero can also obtain fast speed by zapping themselves with a wand of speed monster, or else by eating a quantum mechanic corpse or tin if they do not already have intrinsic speed.
• Slowing attacks, as well as a wand of slow monster or spell of slow monster that the hero zaps at themselves, will remove intrinsic speed but cannot make the hero any slower than their base speed.
• Encumbrance beyond the hero's carrying capacity lowers their effective movement rate, which is the only way a hero can be slowed below their base speed. The hero's speed after adjustments for intrinsic or extrinsic speed and encumbrance are listed in the table below:

Encumbrance	Normal speed	Fast	Very fast	Reduction
Unencumbered	12	16	20	None
Burdened	9	12	15	3⁄4
Stressed	6	8	10	1⁄2
Strained	3	4	5	1⁄4
Overtaxed	1.5	2	2.5	1⁄8

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that the information below is still accurate, then update the page to incorporate it.

Per commit ef1eeed7, blue dragon scales and blue dragon scale mail grant very fast speed.

Multi-turn actions (e.g. entering in "10s" to search ten times) consume one move per command issued, plus whatever additional time is required for these moves. In contrast, certain actions will render the hero immobile or "helpless" for a certain number of turns, during which their movement points are simply drained without allowing them an action. This helpless state can be caused by actions such as fainting, paralysis or engraving a long sentence, and is also logged for the cause of death where applicable.

A hero that is riding a monster has their speed set to that of the steed's monster type, e.g. a hero riding a horse moves at 20 speed, while a hero riding a warhorse moves at 24 speed: kicking a steed or applying a bullwhip to them can make the steed gallop for 20-30 turns, which decreases tameness by 1 and increases their movement speed for automatically repeating forms of movement (e.g. travel or the g command) up to about 1.5 times normal on average. A hero that is polymorphed has their speed set to that of the monster they are polymorphed to, and their base speed mechanics allow them to get more potential movements per turn.

Speed calculations for monsters themselves are explained at length in the section below.

Monster speed

For each monster's base speed, see Monsters (by speed).

The number of moves a monster gets for that turn is distributed based on that monster's speed: the monster's base speed is divided by 12, with the remainder rounded to a multiple of that base speed using weighted randomization. A monster with 12 speed always moves once per turn the hero takes, while a monster with 24 speed moves twice per turn—a monster with speed 18 moves once per turn, with a ¹⁄₂ chance (50%) of an additional move on any given turn, while a monster with 3 speed only gets a ¹⁄₄ chance (25%) of moving each turn. A monster with 0 speed is sessile: they cannot move, attack, gain speed, or lose speed, though they will always have passive attacks.

Monsters can gain or lose speed as the hero does, but cannot gain "very fast" speed, and unlike the hero they can become "slow": a wand of slow monster or spell of slow monster will return a monster that is already fast to normal speed, and will cause a monster at normal speed to become slow. Monsters cannot be slowed by encumbrance, since no monster will pick up more than they can safely carry, and a monster that is carrying more items than they normally can (i.e. as a result of polymorph) will immediately drop whatever they can until this is no longer the case, not counting worn items dropped or destroyed by the polymorph.

A monster's movement rate is adjusted as follows:

• A slow monster has their movement rate lowered to (2 * speed + 1) / 3, e.g. a mountain centaur that is slowed moves at 13 speed (2 * 20 + 1 = 40 + 1, ⁴¹⁄₃ with integer rounding is 13). The absolute minimum movement rate of any abnormally-slowed monster is 1.
• A fast monster has their movement rate raised to (4 * speed + 2) / 3, e.g. a mountain centaur that is fast moves at 27 speed (4 * 20 + 1 = 80 + 1, ⁸¹⁄₃ is 27).

In normal combat, no monster is intended to be able to use their full set of attacks on another monster more than once per turn, regardless of its speed. Pets are given a special exception, since their movement always sets the "after" parameter (which determines whether the monster has already attacked that turn) to 0 after each of their moves: this means that pets with more than 12 speed can attack monsters more often.

Monsters have a ³⁄₄ chance of retaliating against another monster attacking them—a monster will only attack other monsters if motivated to by special interactions (i.e. purple worms and shriekers), conflict or confusion, and will only do so if they have enough movement points left to use up on the action. Against pets, monsters have a ³⁄₄ chance of retaliating against a pet attacking them if they have not attacked that turn, regardless of whether they have movement points.

Strategy

Movement speed is one of the most critical factors in a hero's survival ability, governing their ability to deal damage among other traits, and a source of intrinsic speed at minimum is almost mandatory for every hero's ascension kit. While speed boots are tecnhically optional, they are very frequently worn by most heroes for a majority of the game, since they trade a slot of armor for a general lack of maintenance effort. The haste self spell can be cast repeatedly to gain and maintain extrinsic speed, and can serve as a replacement for speed boots with character builds that are well-suited for spellcasting and can raise their skill in escape spells, such as Monks and Wizards.

Hypothetically, a hero can couple jumping, speed and self-polymorph to move through the dungeon as fast as possible: the air elemental is the fastest monster form at with 36 movement points, though its attacks are relatively weak and it cannot perform most actions that require hands—a hero in air elemental form can still cogitate the labels of scrolls, zap wands and spellcast, and put on amulets. The titan is the fastest form that has hands and is capable of wearing armor at 18 speed, and are very capable fighters with high base AC that compensates for their lack of body armor.

History

In NetHack 3.4.3 and previous versions, including variants based on those versions, for every turn that passes, a monster will gain its movement rate in "movement points"; if the monster has 12 or more movement points (defined as NORMAL_SPEED) in a turn it gets a move that turn (and more than one if it has another 12 points remaining after this, etc.) All monsters including the player have a consistent movement rate: a monster with a speed of 12 gets one move per turn, a monster with a speed of 1 gets one move every 12 turns, a monster with a speed of 18 gets 3 moves every 2 turns (⁴⁄₃ of their normal movement rate), while a monster with 8 speed gets 2 moves every 3 turns (²⁄₃ of their normal movement rate).

In NetHack 3.6.0, at the end of each turn, every monster's remaining movement points are adjusted by a small random amount to reduce the predictability of their actions. On average, monsters will act slightly faster than would be expected by comparing their base speed with that of the hero.

The current speed system is implemented in NetHack 3.6.1.

Maximizing movement in 3.4.3

While jumping in 3.4.3 can be done at any point during a hero's turn, it will always advance them to the next turn and reset the movement counter—the hypothetical fastest movement would have a hero with very fast speed move as far as possible before jumping as their last movement. Using this strategy as an air elemental will allow you to move up to seven squares in a single turn.

The theoretically fastest method of movement, without using life saving, is to be polymorphed into a punished monster with a speed of 24 (e.g. a warhorse), combined with a very fast speed; this gives two actions per turn, plus up to one from the speed, which can be used to throw the heavy iron ball, pick it up again, then (hopefully) jump on the third action, which is slightly faster than moving three times and jumping as an air elemental. However, this is likely too unwieldy to be of much use in practice. (Life saving can be used to reduce helplessness/immobility/paralysis to one turn, allowing hurtling to be the theoretically fastest form of movement, but this is incredibly wasteful of resources, and it is very difficult to arrange a death at the right moment.)

Messages

You speed up.

You gained intrinsic speed from zapping a wand of speed monster at yourself.

You slow down.

You lost intrinsic speed from zapping a wand of slow monster at yourself.

Your quickness feels <more/less> natural.

You gained or lost intrinsic speed while you have a source of very fast speed (e.g., speed boots).

Variants

Many variants of NetHack make it possible for the hero to become slowed from attacks and magic that lower speed, as well as from certain types of terrain.

A variant's speed system will vary depending on the version of NetHack they are built from.

SLASH'EM

SLASH'EM uses the same speed system as NetHack 3.4.3.

SporkHack

SporkHack uses the same speed system as NetHack 3.4.3, with various changed applied: one significant change is that it is possible for the hero to become abnormally slowed like monsters can, and this intrinsic slowness can only be reversed by a potion of speed.

dNetHack

dNetHack, notdNetHack and notnotdNetHack use the same speed system as NetHack 3.4.3, with the addition of a global turn counter.

The wand of speed monster now grants temporary very fast speed, rather than permanent fast speed.

EvilHack

EvilHack uses a similar speed system to NetHack 3.6.1 and later versions in its series, and adapts slowing effect changes from SporkHack to this system.

A hero or monster moving through sewage will be temporarily slowed as they leave that square, unless they have a property or attribute that grants immunity to this effect (e.g. they are a tortle or in the form of a tortle, or else have water walking).