Unique item
In NetHack, a unique item is one of four specific objects required to complete the game, which is listed under the "Unique Items" section in discoveries:
- The Candelabrum of Invocation
- The Bell of Opening
- The Book of the Dead
- The Amulet of Yendor
Generation
Each of the unique items appears in every game, since they are required to win, and cannot ever be wished for as a result. If left in bones, they will revert to the following items:
- The Candelabrum of Invocation is replaced with a stack of candles.
- The Bell of Opening is replaced with a plain bell.
- The Book of the Dead is replaced with a spellbook of blank paper.
- The Amulet of Yendor is replaced with a cheap plastic imitation of the Amulet of Yendor.
Description
Unique items are defined by having the field oc_unique set to 1 in objects.c - while the unique items are also commonly referred to as invocation artifacts, they do not count towards the total of generated artifacts for wishing purposes due to being guaranteed in each game. As they are necessary to win the game, unique items are indestructible (barring bugs) and cannot be placed in containers.
Below is a table that lists each unique item, their effects and the item they revert to if left in bones:
| Artifact name | Bones replacement | Special properties | Obtaining | |
|---|---|---|---|---|
| Carried | Used (worn, wielded, applied, or read) | |||
| Amulet of Yendor | cheap plastic imitation of the Amulet of Yendor | many | Find endgame portals. Sacrifice to win the game! | Obtained from the high priest of Moloch. |
| Bell of Opening | bell | Invocation ritual. Detect secret doors and traps. Opening. | Obtained from your quest nemesis. | |
| Book of the Dead | spellbook of blank paper | Invocation ritual. Tame undead. Raise the dead. | Obtained from the Wizard of Yendor. | |
| Candelabrum of Invocation | stack of candles | Invocation ritual. Radius 4 light. | Obtained from Vlad the Impaler. | |
Unique items versus artifacts
Starting with NetHack 3.0.0, all artifacts are also unique within a given game, but are not the same as unique items - they are specially named variants of their base item with additional benefits, and appear as named versions of those items when unidentified. Some artifacts have a base item that exists mostly or exclusively for the generation of that artifact - e.g., most games will have no more than one runesword or tsurugi, as those items never generate randomly and only appear when Stormbringer or the Tsurugi of Muramasa (respectively) are generated; it is still possible to have multiples of each item, though this typically requires wishing for them or else finding a bones file containing artifacts that have already generated elsewhere in the game.
