# Potion of clairvoyance

! 

Name

Clairvoyance

Appearance

random

Base price

100

Weight

20

Monster use

Will not be used by monsters.

A potion of clairvoyance is a SLASH'EM-specific potion. If uncursed, it grants a single application of clairvoyance, revealing all corridors, walls, and stairs in a 19x11 region around you [1]. Like magic mapping, this does not reveal secret doors, traps, or objects. Unlike magic mapping, however, this works even if the level is designated non-mappable. Unlike the clairvoyance spell, this form of clairvoyance is not blocked by wearing a cornuthaum while not a wizard.
If blessed, the potion grants 100-149 turns of intrinsic clairvoyance, which gives you a 50% chance of mapping the surrounding 19x11 area every 15 turns [2]. This is the same property that can be acquired from donating 200 to 400 times your experience level to an aligned priest, but for a shorter duration than the 500-999 turns received from donating.
A cursed potion will have no effect [3].

Messages
Dude! See-through walls!
You drank a non-cursed potion while hallucinating
Strategy
In a contest between the new-to-SLASH'EM potion of clairvoyance and the existing scroll of magic mapping, magic mapping wins out in most categories. The clairvoyance effect provided by the potion reveals the same tiles as magic mapping, but only in a small fraction of the map, centered on the player. Intrinsic clairvoyance from the blessed potion potentially increases the area that can be mapped, if the player is moving constantly to cover new area for the duration of the potion's effects (which the layout of the level, or its contents, may not permit), and does not fail the 50% roll every 15 turns. Even so, an uncursed scroll of magic mapping (or the spell) can still reveal the entire level in one turn, and in SLASH'EM a blessed scroll detects objects as well, saving the player a potion of object detection to boot. And scrolls weigh 1/4 as much as potions, making a stack of scrolls of magic mapping a better choice for one's kit.
At best a potion of clairvoyance can save the player a few turns searching for secret passages when he/she has no form of magic mapping or is on a non-mappable level where attempting magic mapping would confuse you ("Your mind is filled with crazy lines!"). Most non-mappable levels in SLASH'EM have preset layouts, but the potion may be useful if the player is unfamiliar with the layout and does not wish to consult a map.
Otherwise players may wish to pass up potions of clairvoyance, or save them for dilution for water prayer.

References

↑ potion.c in SLASH'EM 0.0.7E7F2, line 779

↑ potion.c in SLASH'EM 0.0.7E7F2, line 781

↑ potion.c in SLASH'EM 0.0.7E7F2, line 776

This page is a stub. Should you wish to do so, you can contribute by expanding this page.