Shaft

Version 0.31: This article may not be up to date for the latest stable release of Crawl.

A hole in the ground, leading to a dungeon level one or more floors deeper.

Shafts are traps which send the victim down up to 3 floors. Flight has no effect on shafts. There are three distinct types of shaft effect.

Types

Physical Shafts

Physical shafts appear on the floor and are detected immediately on sight. For players, it functions like an escape hatch: you can safely walk over one without being forced down. When standing on a shaft, you can voluntarily enter with >, sending you down 1-3 floors. Unlike stairs or escape hatches, moving through shafts occurs instantly, preventing monsters from following you or getting in free hits against you.

Monsters can fall into physical shafts, as well. Whenever a monster walks over a shaft, it has a chance to fall down. Monsters that are intelligent and with higher HD are less likely to fall down.

Shafts will never appear on the final level of a branch or in single-floor branches, nor do they appear in the Tomb, Abyss, Hell, Pandemonium, or Ziggurats.

Exploration Shafts

Shafts may be triggered randomly by a sourceless malevolence whenever you uncover new tiles. They forcefully send you down 1-3 floors. Exploration shafts are held under the following conditions:

• Ashenzari gives immunity to sourceless malevolence. Formicids, and any species wearing the mountain boots, are immune to shafts.
• Exploration shafts don't trigger in branches where a physical shafts cannot spawn. This excludes Tomb, Abyss, Hell, Pandemonium, Ziggurats.
• Exploration shafts, except in Dungeon, Depths, Lair, and Orc, cannot take you to a branch's final floor.
• Shafts need a valid floor below to drop you to. So you cannot be shafted while on any branch's final floor. And, barring the above exceptions, you cannot be shafted while on the second-to-last-floor.
• Exploration shafts cannot trigger if you are standing on a staircase.
• Exploration shafts can only trigger once per branch.
  • Delvers are considered to have already been "shafted" (from D:1 to D:5), so they cannot be shafted in the Dungeon itself.

In the Dungeon, an exploration shaft will always try to place you in an area without monsters. Shafts on D:1 can only bring you to D:2, and shafts on D:2 can only bring you to D:3 or D:4.

Ignis' wrath may also cause a shaft effect. This is nearly identical to the sourceless malevolence effect, but is triggered by the wrath mechanics instead of through exploration, and can trigger multiple times in one branch.

Formicid Ability

Formicids have an innate ability to shaft themselves. This takes a few turns, but will take them out of immediate danger (though their landing spot is not guaranteed to be safe). Formicids cannot shaft when:

• On the final floor of a branch.
• When inside Abyss, Hell, Pandemonium, or Ziggurats. (Formicids can shaft in the Tomb.)

Strategy

Exploration shafts can be deadly. A drop from D:3 to D:6 can force you to encounter monsters far out of your league, without a guaranteed staircase to escape to. A drop into a vault - a Lair end vault, one of many Depths "encompass" vaults, etc. - can put you into immediate danger. Unfortunately, there is no way to reliable way to prevent sourceless malevolence, other than worshipping Ashenzari.

Physical shafts, on the other hand, can be used to your advantage. Monsters make no effort to avoid stepping on a shaft's tile, so you can lure monsters to drop them down. You'll encounter them on a lower level, but by then, you'll likely have the XP to fight them. Also, in an emergency, you can hop down a shaft to escape downwards. Of course, there's always the danger you may land in a worse situation, but it may be worth the risk.

If you do fall through a shaft to a dangerous depth, a scroll of magic mapping will help you locate nearby stairways and escape hatches to help you return to a safer level.

In the late game, you may want to explore branches in reverse order, solely to defend against shafts. For example, you may want to dive from Zot:1 to Zot:4 (exploring as little as possible), then fully clear Zot:4, then clear Zot:3, Zot:2, and Zot:1 in that order. Note that you should not enter Zot:5 yet, as you cannot be shafted into Zot:5. This reduces the chance of an unavoidable death.

History

• Prior to 0.31, exploration shafts could happen if you were standing on a staircase.
• Prior to 0.30, Delvers didn't have an immunity to exploration shafts in the Dungeon.
• Prior to 0.29, exploration shafts in the Dungeon did not try and place you in a safe location.
• Prior to 0.28, players could be exploration shafted more than once per branch. Also, players couldn't be shafted when on stairs.
• Prior to 0.26, followers of Nemelex could create shafts using the Shaft card.
• Prior to 0.24, player ghosts were immune to shafts.
• Prior to 0.19, items dropped on a shaft could fall through when the shaft collapsed.
• Prior to 0.16, flying creatures were immune to shafts. Also, the chance to escape a shaft was affected by the total (body + equipment) weight for monsters and players.