is a puzzle video game in which the player pushes boxes around in a warehouse, trying to get them to storage locations. The game was designed in 1981 by Hiroyuki Imabayashi, and first published in December 1982.
The warehouse is depicted as a grid of squares, each one representing either a floor section or a wall section. Some floor squares contain boxes and some are marked as 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 number of boxes matches the number of storage locations. The puzzle is solved when all boxes occupy the storage locations.
Progressing through the game often requires meticulous planning and strategic maneuvering. A single misstep, like pushing a box into a corner or blocking others, can create unsolvable scenarios, forcing the player to backtrack or restart the puzzle. Anticipating the consequences of each push, and considering the overall layout of the puzzle are crucial to avoid these deadlocks.[1]
Sokoban was created in 1981 by Hiroyuki Imabayashi.[2] [3] The first commercial game was published in December 1982 by Thinking Rabbit, a software house based in Takarazuka, Japan. Sokoban was a hit in Japan, selling more than 400,000 copies before being released in the United States.[4] In 1988, Sokoban was published in US by Spectrum HoloByte for the IBM PC, Commodore 64, and Apple II as Soko-Ban.[5]
Sokoban has been implemented for almost all home computers, personal computers, video game consoles and even some TVs.[6] Versions also exist for mobile phones, graphing calculators, digital cameras[7] and electronic organizers.
Sokoban has been studied using the theory of computational complexity. The computational problem of solving Sokoban puzzles was first shown to be NP-hard.[8] [9] Further work proved it is also PSPACE-complete.[10] [11]
Solving non-trivial Sokoban puzzles is difficult for computers because of the high branching factor (many legal pushes at each turn) and the large search depth (many pushes needed to reach a solution).[12] [13] Even small puzzles can require lengthy solutions.[14]
The Sokoban game provides a challenging testbed for developing and evaluating planning techniques. [15] [16] The first documented automated solver was Rolling Stone, developed at the University of Alberta. Its core principles laid the groundwork for many newer solvers. It employed a conventional search algorithm enhanced with domain-specific knowledge.[17] Festival, utilizing its FESS algorithm, was the first automatic solver to complete all 90 puzzles in the widely used XSokoban test suite.[18] [19] However, even the best automated solvers cannot solve many of the more challenging puzzles that humans can solve with time and effort.[20] [21]
Several puzzles can be considered variants of the original Sokoban game in the sense that they all make use of a controllable character pushing boxes around in a maze.
This table lists some prominent official Sokoban releases that mark milestones, such as expanding to new platforms or achieving widespread popularity. They are organized by release date.
| Year | Title | Country | Platform | Publisher | Media | |
|---|---|---|---|---|---|---|
| 1982 | Japan | NEC PC-8801 | Thinking Rabbit | Cassette tape | ||
| 1983 | Japan | NEC PC-8801 | PCマガジン | Type-in program | ||
| 1984 | Japan | NEC PC-8801 | Thinking Rabbit | Cassette tape | ||
| 1986 | Japan | Famicom | ASCII | Floppy | ||
| 1988 | Soko-Ban | US | IBM PC, XT, and AT | Spectrum HoloByte | Floppy | |
| 1989 | Japan | NEC PC-9801 | Thinking Rabbit | Floppy | ||
| 1990 | Boxyboy | US | TurboGrafx-16 | NEC | HuCard | |
| 1990 | Shove It! ...The Warehouse Game | US | Sega Genesis | DreamWorks | ROM cartridge | |
| 1991 | Japan | NEC PC-9801 | Thinking Rabbit | Floppy | ||
| 2016 | Japan, US | Android and Apple iOS | Thinking Rabbit | Digital distribution | ||
| 2018 | Japan | Windows | Thinking Rabbit | Digital distribution | ||
| 2019 | Japan | Nintendo Switch and PlayStation 4 | Unbalance | Digital distribution | ||
| 2021 | The Sokoban | US | Nintendo Switch and PlayStation 4 | Unbalance | Digital distribution |