Sokoban

Sokoban is a branch of the dungeon modeled on and named after a game where a character is navigated through a series of levels. The object is to move objects to cover goal squares. The character must move only in the cardinal directions (north, south, east, and west) and push the objects from behind to move them. A player fails by getting objects stuck or boxing himself/herself in, as objects cannot be pulled, created, or destroyed.

In the case of NetHack, the objects are boulders and the goal squares are pits, which block the way forward. There are four levels in each game and two versions of each, for a total of 8 different levels. Diagonal moves are allowed, but only as a shortcut for two moves in cardinal directions. At the end of the Sokoban dungeon branch is a Treasure Zoo guarding a bag of holding or amulet of reflection, depending on which version of level 4 you are given. The levels are ascending in dungeon depth, i.e., the 2nd level is above the 1st etc.

Nethack Sokoban is complicated by the presence of monsters in the puzzles, so some concessions have been made. It is possible to create or destroy boulders, but Luck penalties are assessed for each offense.

Levels

The entrance to Sokoban (an upstairs staircase) is located between levels 5-10, just below the Oracle

	a	b
1	Sokoban Level 1a -------- ------ |<|>...---....| |^|-.00....0..| |^||..00|.0.0.| |^||....|.....| |^|------0----| |^| |......| |^------......| |..^^^^0000...| |??-----......| ---- --------	Sokoban Level 1b ------ ----- |....| |...| |.0..----.0.| |.0......0..| |..---@---0.| |---------.--- |..^^^<|.....| |..----|0....| --^| |.0...| |^-----.0...| |..^^^^0.0..| |??---------- ----
2	Sokoban Level 2a ---- ----------- --.@-------- |.........| |..........| |.........| |.0-----0-.| |.........| |..|...|.0.| |....<....| |.0.0....0-| |.........| |.0..0..|..| |.........| |.----0.--.| |.........| |..0...0.|.-- |.........| |.---0-...0.------------+| |...|..0-.0.^^^^^^^^^^^^.| |..0......---------------- -----..|..| -------	Sokoban Level 2b ----------- ----------- |....|....--- |.........| |..00|00...@| |.........| |.....0...--- |.........| |....|....| |....<....| |-.--------- |.........| |..0.|.....| |.........| |.00.|0.0.0| |.........| |..0.....0.| |.........| |.000|0..0.----------------+| |....|..0.0.^^^^^^^^^^^^^^^.| -----------------------------
3	Sokoban Level 3a -------- ---.|....| |...0....|---------- |.-.00-00|.|.......| |.00-......|.......| |.-..0.|...|.......| |....-0--0-|...<...| |..00..0...|.......| |.--...|...|.......| |....-0|---|.......| ---..0.-----------+| |..0@^^^^^^^^^^^.| ------------------	Sokoban Level 3b -------------------- |........|...|.....| |.00..-00|.-.|.....| |..|.0.0.|00.|.....| |-.|..-..|.-.|..<..| |...--.......|.....| |...|.0.-...-|.....| |.0.|0.|...--|.....| |-0.|..-----------+| |..0....^^^^^^^^^^.| |...|.@------------- --------
4	Sokoban Level 4a (with a bag of holding) -------------------------- |@......^^^^^^^^^^^^^^^^.| |.......----------------.| -------.------ |.| |...........| |.| |.0.0.0.0.0.| |.| --------.----| |.| |...0.0..0.0.| |.| |...0........| |.| -----.-------- ------|.| |..0.0.0...| --|.....|.| |.....0....| |.+.....|.| |.0.0...0.-- |-|.....|.| -------.---- |.+.....+.| |..0.....| |-|.....|-- |........| |.+.....| |...------ --|.....| ----- -------	Sokoban Level 4b (with an amulet of reflection) ------------------------ |..^^^^^^^^^^^^^^^^^^..| |..-------------------.| ----.| ----- |.| |..|0-- --...| |.| |.....|--|.0..| |.| |.00..|..|..0.| |.| --..00|...00.-- |.| |0..0...|0..| ------|.| |.00.|..|..0| --|.....|.| |.0.0---|.0.| |.+.....|.| |.......|..-- |-|.....|.| ----.0..|.-- |.+.....+.| ---.--.| |-|.....|-- |.0...| |.+.....| |@.|..| --|.....| ------- -------

Strategy

The articles about the individual levels contain a full solution to all the levels. Some general strategy tips include

• Think ahead, the entire level is mapped and all the levels are solvable without 'cheating'.
• Be careful, a typo may render a boulder immobile against the wall.
• Check whether there are monsters in front of the pits.
• Use a magic whistle for pets, or leave them behind one level.
• Be aware of giant mimics imitating boulders.
• Upon completion, check under unmoved boulders for useful items.
• Polymorphing into a creature with the phasing ability will not help. Instead, you get the message "The Sokoban walls resist your ability."

Strategies for when a boulder got stuck:

• Destroy a boulder with a pick axe or wand of striking (count whether there are enough!)
• Drop everything in your inventory (including armor) and squeeze into the same square as a boulder.
• Summon more boulders with a scroll of earth, which can be found on the 1st sokoban level.
• If the boulder is stuck because of a monster behind it, you can shoot missiles past the boulder to kill the monster.

The first level of sokoban, once completed, is often used as a stash level, for several reasons:

• It is one of the locations which the Eye of the Aethiopica can teleport you to instantly.
• It is conveniently located, two levels from the Oracle, 2-8 levels from the Gnomish Mines, and located in the top half of the Dungeons of Doom, where shops and altars are likely.
• It is relatively free of monsters, and a spawning ground for baby monsters rather than their larger versions.
• There are spare boulders which can be used to further block off a safe area.

The first level also contains two scrolls of earth. Remember to #name them as such as soon as you find them.