Jumping
Jumping is a property that allows a player to traverse multiple empty tiles in one movement. The ability to jump comes from three sources: being a Knight, wearing jumping boots, or casting a spell of jumping. To perform a jump, use the extended command #jump. If number_pad is set, you can also press j. Knight jumping and jumping from the boots are practically identical; the only difference is to which squares you can jump. The spell lets you jump farther, depending on your skill in escape spells.
Using any of the three sources to jump, you must be able to see your destination. The jump will consume d25 nutrition (plus the usual spellcasting hunger penalty, if you cast the spell), and you become immobile for the rest of the current turn (not simply one action) after landing.[1] (This penalty thus has no effect if you use it on the last action of a turn.) Players with speed can move farther in one turn by stepping as far as possible without advancing the turn counter, then jumping, see Speed#Strategy.
Note that you cannot jump over monsters. If you attempt to do so, you will bump into them, which will wake them up and anger them if they are peaceful.
You can jump to try to escape from a pit or lava. You can also jump out of a web, which will tear it apart. You can jump out of a bear trap, but it will cause 1d10 damage and can inflict a long-lasting leg wound. If you are stuck in the floor (because you were caught in cooling lava) and attempt to jump, you will remain stuck and wound your legs. Jumping out of shops counts as direct theft.
Range
In the following diagrams, tiles to which you can jump are marked by an 'x'.
Knight's jump ........... |
Jumping boots ........... |
||
| Jumping spell | |||
|---|---|---|---|
Unskilled ........... |
Basic ........... |
Skilled ........... |
Expert ........... |
Path
Once you select a destination, you will be moved towards it along a path determined by a version of Bresenham's line algorithm.[2] The path will be as close to a straight line as possible, but will tend to move you along the longer axis of your jump. It will never move you a greater proportion of the distance along the shorter axis than it has moved you along the longer axis.
The following diagrams illustrate the non-trivial paths:
......... ......... ......... ...X.X...
......... ...X.X... ..X...X.. ...*.*...
...X.X... ...*.*... .X.*.*.X. ....*....
..X.*.X.. .X*.*.*X. ..**.**.. X*..*..*X
...*@*... ...*@*... ....@.... ..**@**..
..X.*.X.. .X*.*.*X. ..**.**.. X*..*..*X
...X.X... ...*.*... .X.*.*.X. ....*....
......... ...X.X... ..X...X.. ...*.*...
......... ......... ......... ...X.X...
Note that some jumping paths are asymmetrical; for example, in the first diagram, if you jump north-northwest, and there's an obstacle one square south of your destination, you'll pass to its east, but you'll bump into it if you try to jump back to your origin.
Knowing the path of your jump is important for maximizing jump distance, and to avoid angering peaceful monsters.
Restrictions
You cannot jump if:
- You lack the means to jump: you are not wearing jumping boots, not casting the jumping spell, and are not a Knight.
- You are engulfed by a monster.
- You are in water.
- You are stuck to a monster, unless it is tame and not suffering from confusion or conflict.
- You are levitating or on the Plane of Air or Water.
- You or your steed have wounded legs.
- Your steed is stuck in a trap.
In addition, if you are not casting the jumping spell, you cannot jump if:
- You are polymorphed into something with no legs (e.g., a slithy monster).
- You are burdened to any degree.
- You are hungrier than the halfway point between not hungry and weak.
- You have less than six strength.
But you can surprisingly jump if:
- You are stunned or confused (and you even land in the right place).
- You are riding a paralysed steed.
- You are riding a flying steed.
Messages
- You can't jump very far.
- You attempted to #jump, but you have no source of jumping.
- You pass right over a <trap>.
- You jumped over a previously known trap, without activating it.
- You bump into a <monster>.
- You attempted to jump onto or past a monster, and crashed into them instead.
- You find a <monster> by bumping into it.
- As above, but the monster was previously hiding.
- You find something by bumping into it.
- As above, but the monster was previously invisible to you.
- Too far!
- You selected a jump destination that was too far away.
- Illegal move!
- You are a knight (with no other sources of jump), and your destination is not a chess knight's-move away.
- There is an obstacle preventing that jump.
- Your jump path is blocked by something, e.g. a wall.
- You cannot see where to land!
- Your jump destination is not visible.
- You cannot jump there!
- Your jump destination is invalid.
- You can't jump diagonally out of a doorway.
- You are standing in a doorway and your jump path would take you diagonally out of it.
- You can't jump; you have no legs!
- You are polymorphed into a form with no legs.
- You lack the strength to jump!
- You have less than 100 nutrition points, or have less than 6 Strength.
- Your [left |right |]leg is in no shape for jumping.
- You have wounded leg(s).
- You are carrying too much to jump!
- You are not unencumbered.
- You don't have enough traction to jump.
- You are levitating, or on the Plane of Air or Water.
- You flail around a little.
- As above, but when jumping magically.
- You cannot escape from the <monster>!
- You are stuck to a hostile monster, or a pet suffering from confusion or conflict.
- You writhe a little in the grasp of the <monster>!
- As above, but when jumping magically.
- This calls for swimming, not jumping!
- You are attempting to jump whilst in water.
- You swish around a little.
- As above, but when jumping magically.
- You've got to be kidding!
- You are attempting to jump whilst engulfed by a monster.
- You bounce around a little.
- As above, but when jumping magically.
History
Before NetHack 3.6.1, the #jump command would not cast the jumping spell. To cast it in previous versions and variants based on them, you must press Z and select jumping.
Strategy
Jumping is an excellent escape method. For this reason, a minority of seasoned players value jumping boots over speed boots.
If you want to eat a corpse for an intrinsic, but you are satiated and don't have an amulet of magical breathing, jumping can un-satiate you. This goes especially if you have hungerless casting.
Clearing a lane with a wand of teleportation, then jumping through it, is one of the better strategies for the Astral Plane. Since you need to be able to see your destination, many players carry the Candelabrum of Invocation to the Endgame.
See Speed#Strategy to learn the fastest way to move around the dungeon. But watch your nutrition intake, especially in the early game.
You can avoid traps by jumping over them, except fire traps, magic portals and Sokoban traps. Jumping over the vibrating square will still reveal it. Before NetHack 3.6.1, you could jump diagonally through open doors; this is no longer possible. [3] However, if you got inside a closed door by phasing, you can jump diagonally out of it without needing the power.
You can cross Medusa's Lair by jumping from island to island. However, you really want a levitation source for the Endgame anyway, so you might want to turn back and get one instead.
Origin
The Knight's odd set of jump targets – one square orthogonally, then one square diagonally away from the square of origin – is a reference to chess, in which the piece called the knight moves in the same way, jumping over any pieces between the starting and landing squares.
References
- ↑ apply.c in NetHack 3.4.3, line 1361
- ↑ apply.c, line 1354 calls walk_path in dothrow.c, which calculates the path
- ↑ src/apply.c in NetHack 3.6.1, line 1576
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It may contain text specific to NetHack 3.6.1. Information on this page may be out of date.
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