Boulder
- For the option, see option#boulder.
| Item classes | ||
|---|---|---|
| " Amulets | [ Armor | |
| % Comestibles | $ Coins | |
| * Gems | ! Potions | |
| = Rings | ? Scrolls | |
| + Spellbooks | ` Statues | |
| ( Tools | ` Boulders | |
| ) Weapons | / Wands | |
A boulder, `, is a type of huge stone object that appears in NetHack. Although boulders are considered items, they are large enough to also block line of sight, and are too heavy for you to lift normally - as such, they tend to resemble a dungeon feature more than an item in practice.
The boulder symbol is customizable through the boulder option; many players choose to change the symbol for boulders to make them more noticeable, particularly during Sokoban, and 0 (zero) is a popular choice.
Contents
Generation
Boulders are usually randomly placed during level creation, and are generally found in corridors. A boulder trap consists of a trigger square and a single boulder placed out in the open, usually within the same room; if you or another monster steps on that square, the boulder will roll to the other side of the trap, usually hitting that monster and anything else in the path.
Reading a scroll of earth will cause one or several boulders to fall; if read while confused, several rocks will fall. Reading an uncursed scroll will cause one to fall in each square around you and on you, and reading a blessed scroll omits the boulder that would land on you - reading a cursed scroll causes a single boulder to fall on you.
Sokoban is a dungeon branch dedicated to puzzles where boulders are used to fill pits, and Luck penalties are usually assigned for creating or breaking boulders in this branch on an unsolved floor.
Polymorphing statues will sometimes produce boulders. Boulders that are shattered will leave behind 6 + d60 rocks.
Boulders can be wished for one at a time, but unless you are in the form of a giant or titan, the boulder will immediately be dropped to the floor.
Monsters
Dwarves wielding pick-axes or dwarvish mattocks, as well as other tunneling NPC monsters, will leave behind boulders while digging around the level.[1]
Non-undead giants and titans that are randomly generated have a 1⁄2 chance of being given a boulder.[2]
Description
You and other monsters cannot attack through boulders, but can use missile weapons, wands, and spells to attack through them. A pick-axe, a dwarvish mattock, or a force bolt (from the spell or a wand of striking) will shatter boulders into several rocks - other wands and spells, particularly the wand of digging, will have no effect on the boulder. Monsters will not target a wand of striking at boulders intentionally, and typically do so as a side effect of targeting you.
Moving boulders
You and most other monsters cannot travel past boulders unless you have phasing - if you move onto a square containing a boulder, you will try to push it to the next square in line. When there is more than one boulder on a square, you will try to push each boulder in turn until one of them does not move; you cannot push any boulders if you are levitating, due to lack of leverage. Pushing boulders exercises strength.
Boulders that have a wall or other obstruction in the direction of the pushing movement cannot be moved, but you can "squeeze" through if you have an empty inventory (not counting any gold) or are 850 or more units below your carrying capacity.[3] Pushing a boulder into a hole, trap door or either type of pit will usually plug it and turn that square into normal floor.
Pushing a boulder into a moat will fill it 9⁄10 of the time and create a floor tile that you can move across, and the remaining 1⁄10 of the time it will disappear with no effect. This probability is reversed for lava, which causes the boulder to fill the square only 1⁄10 of the time, and disappear otherwise - lava will splash onto you in either case, dealing 3d6 damage; fire resistance reduces this to d6 damage, and the damage can also be reduced by the half physical damage property.
Boulders have a 3% chance of falling down stairs if another thrown object lands on their square; this includes gold, but not rocks and gems.[4] You can also push them onto a teleport trap or level teleporter, though there is a very low chance of it landing on the down stair's square.
Boulders and giants
Non-undead giants (including titans) can move over boulders, pick them up and even throw them - you can do the same if polymorphed into a giant as well. Boulders in a giant's inventory have no weight, as opposed to the 6000 aum they would weigh otherwise; you can pick one up even if all other inventory letters are in use, and it will be assigned a hash mark inventory slot (#) also used by loadstones.
If a giant throws a boulder at you, it will land on your square regardless of if it actually hits you - you may move off the square as normal, but attempting to re-enter the square will require pushing the boulder out of the way. If you have displacement, or you are invisible and the giant throwing the boulder cannot see invisible, a thrown boulder that misses will instead land at where the giant thought you were.
Boulder traps
As mentioned above, boulder traps will cause a pre-placed boulder to roll towards the trap, possibly crushing whatever triggered it and anything else in its path. The boulder will always roll in a way such that it ends up on the opposite end of the trap at an equal distance away (e.g., a boulder 3 squares to the left of the trap will roll until it is 3 squares to the right). Moving the boulder off its starting position will render the trap useless, and it will disappear if triggered afterward unless replaced on that square - this also applies if the rolling boulder fills a pit, hole or trap door, runs into another boulder or obstruction in its path, or it is caught by a giant that was in the way.
Boulders and other traps
A user has suggested improving this page or section as follows:
"There may be some research to be done pertaining to trapdoors."
While boulders can be used to fill holes and pits (including spiked pits), the exact interactions and effects depend on a few factors, including: whether the boulder or the pit/hole occupied the square in question first; the source of a boulder that is moved into a pit or hole; the source of a pit or hole that occurred in a square with a pre-existing boulder; and where you are standing in relation to the pit or hole.
Pushing a boulder into a pit or hole removes the boulder and the plugged trap, regardless of whether or not its location was known to the player character; items on the square of the pit or hole are buried. Boulders that land on the square of a pit or hole as a result of being thrown, dropped, sent from the sky by a scroll of earth, or else rolled via boulder trap will plug that trap and remove it, burying items as normal.
If you are trapped in a pit and a boulder is dropped or rolled in on top of you, the effect varies depending on if you are a giant or not. If you are a giant, the pit is filled and you are instantly freed from it without any further effect - if you are not a giant, the pit will not be filled, and there is a chance during each attempt to escape the pit that it is filled by the boulder, leaving your leg is stuck in a leftover crevice that you must pull free from. Zapping a wand of teleportation down or applying it while the boulder is still on that square will teleport it elsewhere, allowing you to try escaping the pit as normal. Holes that are filled while you are on their square will be plugged, just as if you were standing next to that hole.
Applying a charged drum of earthquake can create a pit underneath a boulder, which immediately fills the pit and also buries every item on that square underneath it[5] - interestingly, if there are multiple boulders on that square (e.g., usually from a giant dropping them all at once), they will also be buried, minus the boulder that fills the pit. If you are on top of a boulder and zap a wand of digging down on that square, you will create a hole or pit depending on the whether the level is diggable, and the trap is plugged immediately before anything can fall through or into it.[6] If a boulder is already present on a square with a pit, and you manuever into that square and zap a wand of digging down, the boulder will fill the pit instead of creating a hole, with two different messages possible.[6]
It is possible to get a boulder on top of a pit or hole outside of wizard mode by dropping a statue on top of the square via levitation; you also have a 1⁄5 chance of avoiding a known pit or hole when moving onto its square, and can drop the statue once after successfully avoiding falling in. If you then polymorph the statue into a boulder, it will drop into and fill a pit, but not a hole - throwing other objects at a boulder that is placed on the same square as a hole in this way will cause it to fall through the hole and land on a lower level, as with boulders on a downward staircase.
You cannot dig down with a pick-axe while on a square with a boulder. Breaking a wand of digging will not create a hole or pit under a boulder, due to special checks in the code.[7][8][9]
Strategy
Boulders are often used to protect stashes or polytraps by pushing one on top of the stash or even many boulders around it as a fort.
Other Uses
To get past a boulder, the player may break it into rocks with a , wand of striking or force bolt. This will transform it into . A spell of stone to flesh turns a boulder into a huge chunk of meat, which is a normal item with none of the boulder's unique properties.
Tactics for pushing boulders
If [[you push a boulder, then it will move to the opposite square. In the diagrams below, the # represents where the boulder will move. Boulders on each floor of Sokoban cannot be moved diagonally while solving that level; as of 3.6.1, they can be moved normally once the level is solved.
If there is no space or if it is occupied by a monster (whether hostile, peaceful, or your pet) then you cannot move the boulder in that direction. Failing to push a boulder will not consume a turn. If your inventory is mostly empty, you can squeeze onto the square containing the boulder. (The fastest way to drop your inventory is to press D and then choose option "A" to drop all items.) Such squeezing is useful if there is a door, hidden space, or boulder on the other side.
If a monster blocks the other side and will not move away, you have the option of squeezing onto the boulder and fighting it bare-handed and naked, or you can throw ammunition or Mjollnir or zap wands past the boulder. Be careful when doing so if you cannot see your pets, as they may be the monster blocking you or directly behind it. The player below might want to toss darts, rocks, or other objects at whatever is blocking the way to some holes ^ in Sokoban.
You can move diagonally around boulders (but not in Sokoban) regardless of how much you are carrying. So the following boulder does not block your path provided that you know how to use [yubn] or numpad to move diagonally:
##`##
If a boulder is blocking a corridor, and if you are able to push it into a room or into a position like the above, then you can walk around it.
When faced with two consecutive boulders in a corridor, as shown below, you can squeeze past one to push the other.
However, wandering around naked with no wielded weapon, or allowing hostile monster to take from your inventory, might put you in too much danger. You might want to push the other boulder and retrieve your inventory quickly. (The fastest way to retrieve the inventory is to press @ to toggle autopickup on and then move onto the square where you dropped it. Then you might want to press @ again to toggle autopickup off.)
Boulders, like anything else, cannot pass diagonally through open doors. If you need to do that, destroy the door by closing it with c and then kicking it down with Control-D.
The two boulders below are stuck against a wall, and you may only push them in two directions:
|...`.....| |....| -------
|.........| #####..`...####......|
|.........| # ------ |.....|
---.------- ### -------
If a boulder becomes stuck in a corner, then you can not move it at all, even if you squeeze onto its square (unless you are able to dig around it). In Sokoban, a 2x2 square of four boulders (or a 2x2 square of both boulders and walls) is almost likewise stuck, but you might be able to squeeze yourself to free the boulders. (Squeezing causes a luck penalty in Sokoban.) Outside of Sokoban you could have freed a boulder by moving it diagonally, but not if you have two boulders stuck against the same wall.
An example of stuck boulders:
---- ----
|`.. .``.
|... ....
An example of boulders that are stuck only in Sokoban:
...... ...|..
..``.. ---`..
..``.. ..``..
...... ......
Be very careful in Sokoban to not stick boulders in the above manners unless you are able to solve the level with the remaining boulders.
Encyclopedia entry
I worked the lever well under, and stretched my back; the end
of the stone rose up, and I kicked the fulcrum under. Then,
when I was going to bear down, I remembered there was
something to get out from below; when I let go of the lever,
the stone would fall again. I sat down to think, on the root
of the oak tree; and, seeing it stand about the ground, I saw
my way. It was lucky I had brought a longer lever. It would
just reach to wedge under the oak root.
Bearing it down so far would have been easy for a heavy man,
but was a hard fight for me. But this time I meant to do it
if it killed me, because I knew it could be done. Twice I
got it nearly there, and twice the weight bore it up again;
but when I flung myself on it the third time, I heard in my
ears the sea-sound of Poseidon. Then I knew this time I
would do it; and so I did.
References
- ↑ src/dig.c in NetHack 3.6.6, line 1328
- ↑ src/makemon.c in NetHack 3.6.6, line 183
- ↑ hack.c in NetHack 3.4.3, line 287
- ↑ dokick.c in NetHack 3.4.3, line 1201
- ↑ music.c in NetHack 3.4.3, line 286
- ↑ 6.0 6.1 dig.c in NetHack 3.4.3, line 684
- ↑ apply.c in NetHack 3.4.3, line 2698: Breaking the wand calls dig_check in dig.c
- ↑ dig.c in NetHack 3.4.3, line 196: dig_check checks for boulders
- ↑ do_earthquake in music.c: This function does not call dig_check
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