is a

puzzle video game Puzzle video games make up a broad genre of video games that emphasize puzzle solving. The types of puzzles can test problem-solving skills, including logic, pattern recognition, Sequence, sequence solving, Spatial ability, spatial recognition, ...

in which the player pushes boxes around in a

warehouse A warehouse is a building for storing goods. Warehouses are used by manufacturers, importers, exporters, wholesalers, transport businesses, customs, etc. They are usually large plain buildings in industrial parks on the rural–urban fringe, out ...

, trying to get them to storage locations. The game was designed in 1981 by Hiroyuki Imabayashi and first published in Japan in 1982 by his company Thinking Rabbit for the NEC PC-8801 computer. It was later ported to various platforms and followed by new titles. It became popular in Japan and internationally, inspiring unofficial versions, a subgenre of box-pushing puzzle games, and artificial intelligence research.

Gameplay

The warehouse is a grid composed of floor squares and impassable wall squares. Some floor squares contain a box and some are marked as storage locations. The number of boxes equals the number of storage locations. The player, often represented as a worker character, can move one square at a time horizontally or vertically onto empty floor squares, but cannot pass through walls or boxes. To move a box, the player walks up to it and pushes it to an empty square directly beyond the box. Boxes cannot be pushed to squares with walls or other boxes, and they cannot be pulled. The puzzle is solved when all boxes are on storage locations. Progressing through the game requires careful planning and precise maneuvering. A single mistake, such as pushing a box into a corner or obstructing the path of others, can render the puzzle unsolvable, forcing the player to backtrack or restart. Anticipating the consequences of each push and considering the overall layout of the puzzle are crucial to avoid deadlocks and complete the puzzle successfully.

History

''Sokoban'' was created in 1981 by Hiroyuki Imabayashi. The first commercial game was published for the NEC PC-8801 computer in December 1982 by his company, Thinking Rabbit, based in Takarazuka,

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

Ports Ports collections (or ports trees, or just ports) are the sets of makefiles and Patch (Unix), patches provided by the BSD-based operating systems, FreeBSD, NetBSD, and OpenBSD, as a simple method of installing software or creating binary packages. T ...

and new titles for various platforms appeared in subsequent years. In 1988, Spectrum HoloByte published ''Sokoban'' in the U.S. for the

IBM PC The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the List of IBM Personal Computer models, IBM PC model line and the basis for the IBM PC compatible ''de facto'' standard. Released on ...

Commodore 64 The Commodore 64, also known as the C64, is an 8-bit computing, 8-bit home computer introduced in January 1982 by Commodore International (first shown at the Consumer Electronics Show, January 7–10, 1982, in Las Vegas). It has been listed in ...

, and

Apple II Apple II ("apple Roman numerals, two", stylized as Apple ][) is a series of microcomputers manufactured by Apple Computer, Inc. from 1977 to 1993. The Apple II (original), original Apple II model, which gave the series its name, was designed ...

as ''Soko-Ban''. In 1990, Fujisankei Communications International, FCI released ''Boxxle'' for the Game Boy in both North America and Europe, followed by ''Boxxle II'' in 1992. Between 1996 and 2000, several ''Sokoban'' games were released for Microsoft Windows, Windows and PlayStation (console), PlayStation in Japan. In 2001, the Japanese software company Falcon acquired the trademarks for ''Sokoban'' and Thinking Rabbit. Since then, Falcon has continued to develop and license official ''Sokoban'' games.

Versions

Since its debut in 1982, ''Sokoban'' has been released on various platforms, primarily in Japan but also in other regions. Most titles are independent without a continuous narrative or unified series, though a few are direct sequels to a specific earlier release—for example, ''Sokoban 2'' (1984) follows ''Sokoban'' (1982), and ''Soko-ban Revenge'' (1991) is a sequel to ''Soko-ban Perfect'' (1989). The following table lists a selection of official ''Sokoban'' titles.

Reception

By June 1984, the original ''Sokoban'' had sold 22,000 copies in Japan; by March 1985, it had reached 30,000 copies. ''Sokoban'' was a hit in Japan, selling over 400,000 copies before being released in the United States. The 1988 American release, ''Soko-Ban'', received a positive review from ''

Computer Gaming World ''Computer Gaming World'' (CGW) was an American Video game journalism, computer game magazine that was published between 1981 and 2006. One of the few magazines of the era to survive the video game crash of 1983, it was sold to Ziff Davis in 199 ...

'', which described the game as simple yet mentally challenging, and praised its addictive nature.

Legacy

Cultural impact

An active fan community has produced thousands of custom puzzles, unofficial versions, and software tools, including puzzle editors, solvers, and solution optimizers.

Derivatives

''Sokoban'' is considered the originator of a puzzle game subgenre featuring box-pushing mechanics, commonly referred to as "Sokoban-like" games. * Alternative tilings: While ''Sokoban'' is played on a square grid, its fundamental rules are, in principle, applicable to boards with other tilings. ''Hexoban'' exemplifies this, utilizing regular hexagons. * Multiple pushers: In the variant ''Multiban'', the puzzle contains more than one pusher. In the game ''Sokoboxes Duo'', strictly two pushers collaborate to solve the puzzle. * Designated storage locations: In ''Sokomind Plus'', some boxes and target squares are uniquely numbered. In ''Block-o-Mania'', the boxes have different colours, and the goal is to push them onto squares with matching colours. * Alternative game objectives: Several variants feature different objectives from the traditional ''Sokoban'' gameplay. For instance, in ''Interlock'' and ''Sokolor'', the boxes have different colours, and the objective is to move them so that similarly coloured boxes are adjacent. In ''CyberBox'', each puzzle has a designated exit square, and the objective is to reach that exit by pushing boxes, potentially more than one simultaneously. In a variant called ''Beanstalk'', the objective is to push the elements of the puzzle onto a target square in a fixed sequence. * Additional game elements: ''Push Crate'', ''Sokonex'', ''Xsok'', ''CyberBox'', and ''Block-o-Mania'', all add new elements to the basic puzzle. Examples include holes, teleports, moving blocks and one-way passages. * Character actions: In ''Pukoban'', the character can pull boxes in addition to pushing them. * Reverse mode: Some Sokoban programs allow players to play a puzzle backward. This approach can help players better understand the puzzle structure and develop effective solving strategies. Starting with all boxes on storage locations, the player pulls the boxes to return to the initial puzzle state. Solutions found this way solve the standard puzzle when both the order and the direction of the moves are reversed.

Computer science research

''Sokoban'' has been studied using the theory of

computational complexity In computer science, the computational complexity or simply complexity of an algorithm is the amount of resources required to run it. Particular focus is given to computation time (generally measured by the number of needed elementary operations ...

. The computational problem of solving ''Sokoban'' puzzles was first shown to be

NP-hard In computational complexity theory, a computational problem ''H'' is called NP-hard if, for every problem ''L'' which can be solved in non-deterministic polynomial-time, there is a polynomial-time reduction from ''L'' to ''H''. That is, assumi ...

. Further work proved it is also

PSPACE-complete In computational complexity theory, a decision problem is PSPACE-complete if it can be solved using an amount of memory that is polynomial in the input length (PSPACE, polynomial space) and if every other problem that can be solved in polynomial sp ...

. Solving non-trivial ''Sokoban'' puzzles is difficult for computers because of the high

branching factor In computing, tree data structures, and game theory, the branching factor is the number of children at each node, the outdegree. If this value is not uniform, an ''average branching factor'' can be calculated. For example, in chess, if a "node ...

(many legal pushes at each turn) and the large search depth (many pushes needed to reach a solution). Even small puzzles can require lengthy solutions. The ''Sokoban'' game provides a challenging testbed for developing and evaluating

planning Planning is the process of thinking regarding the activities required to achieve a desired goal. Planning is based on foresight, the fundamental capacity for mental time travel. Some researchers regard the evolution of forethought - the cap ...

techniques. The first documented automated solver, Rolling Stone, was developed at the

University of Alberta The University of Alberta (also known as U of A or UAlberta, ) is a public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta, and Henry Marshall Tory, t ...

. It employed a conventional search algorithm enhanced with domain-specific techniques such as deadlock detection. A later solver, Festival, introduced the FESS search algorithm and became the first automatic system to solve all 90 puzzles in the widely used XSokoban test suite. Despite these advances, even the most sophisticated solvers cannot solve many highly complex puzzles that humans can solve with time and effort, using their ability to plan ahead, recognize patterns, and reason about long-term consequences.

Notes

References

External links

Official Sokoban site
(in Japanese)
The University of Alberta Sokoban page
{{DEFAULTSORT:Sokoban 1982 video games Apple II games ASCII Corporation games BBC Micro and Acorn Electron games Cancelled Atari Jaguar games Commodore 64 games DOS games FM-7 games GP2X games Linux games Logic puzzles MacOS games Maze games MSX games NEC PC-6001 games NEC PC-8001 games NEC PC-8801 games NEC PC-9801 games Puzzle video games SG-1000 games Sharp MZ games Sharp X1 games Single-player video games Spectrum HoloByte games Thinking Rabbit games Video games developed in Japan Windows games Windows Mobile Professional games X68000 games ZX Spectrum games