Sokoban[a] is a series of puzzle video games in which the player pushes boxes around in a warehouse. The aim of the game is to get the boxes onto storage locations. Hiroyuki Imabayashi created the first Sokoban game in 1981 as a hobby, and the following year, his company Thinking Rabbit published an enhanced commercial version in Japan for the NEC PC-8801 computer. Over the years, new titles were released for various platforms, developed by Thinking Rabbit or other companies under license. The game became popular in Japan and internationally, and the official series has remained active, with its most recent title released in 2021. Sokoban has inspired unofficial versions, thousands of custom puzzles, similar games, and artificial intelligence research.
The puzzles in Sokoban require the player to push boxes to designated spots (shown as red dots in the animation) in the game world.
Sokoban takes place in a warehouse viewed from above and composed of walls and floor squares. A floor square may be empty, occupied by the player, or occupied by a box. Some floor squares are marked as storage locations. The number of storage locations equals the number of boxes. The objective of the puzzle is to push all boxes onto storage locations.[1]
The player can move one square at a time, either horizontally or vertically, onto an empty floor square.[2] Boxes and walls block the player's movement, but the player can walk up to a box and push it to an empty square directly beyond it. If a box is pushed against a wall or another box, it does not move. Pulling boxes is not possible.[3]
Playing Sokoban requires thinking several steps ahead and visualizing all possible outcomes.[4] Players must think carefully and thoroughly before pushing a box to prevent it from being permanently trapped against a wall or other boxes,[2] or in a dead end.[5] These are deadlocks from which the puzzle cannot be solved, regardless of subsequent moves.[6]
History
In 1981, Hiroyuki Imabayashi created the first Sokoban game as a hobby for the NEC PC-8001 computer. The game used text-based graphics and featured five levels designed by him. For the core mechanic, he was inspired by a part of the gameplay in Hudson Soft's 1980 action game, Aldebaran #1, for the MZ-80K,[7] where the player pushed luggage to act as a wall to prevent radiation.[8] Imabayashi conceptualized that in the warehouse, the boxes had to be organized, but that they themselves would obstruct the organizing process. He worked to design levels that provided a real challenge, and friends he invited to his home to play the game struggled to solve them. At that time, his wife's parents owned a record store with a small computer section. By chance, a salesman saw the game and suggested that it would sell.[9] Imabayashi used a NEC PC-8801 computer in the store's computer section to port the game, enhancing the graphics and expanding the levels to twenty. In 1982, he founded his company, Thinking Rabbit, based in Takarazuka, Japan, and released this PC-8801 version as the first commercial Sokoban game in December.[10][11]
In 1983, the Japanese magazine PC Magazine published Sokoban Extra Edition as a type-in program featuring ten new puzzles. This game was developed by Thinking Rabbit under request.[12] In 1984, Thinking Rabbit published Sokoban 2, featuring a puzzle editor.[13] Throughout the rest of the 1980s, new titles appeared on a variety of Japanese platforms, including home computers such as the MSX and PC-9801, and video game consoles such as the Famicom, Sega SG-1000, Sega Mega Drive, and Game Boy.[14] These releases were developed either by Thinking Rabbit or by other companies under license agreements.[10] In 1987, Spectrum HoloByte, based in California, U.S., acquired a license from Japan's ASCII, and ported and adapted the MSX version of Sokoban to IBM PC, Apple II, and Commodore 64, adding features for the U.S. market, and released it as Soko-Ban in the United States early in 1988.[15][16] In the 1990s, the official series continued in Japan with further titles for the Super Famicom, Windows, Macintosh, and PlayStation.[17]
Around 2000, Thinking Rabbit became inactive but remained a legal entity.[8] In 2001, the Japanese software company Falcon acquired the copyright to the official Sokoban games and the trademarks for Sokoban and Thinking Rabbit,[18] becoming the official developer and licensor of the series. From 2004 to 2007, Falcon developed several titles for Japanese mobile phones.[19][20] Starting in 2015, it also developed several Sokoban titles for Windows and, in 2016, the smartphone game Sokoban Touch, all published under the Thinking Rabbit brand.[17] In 2018, Falcon also developed three Sokoban titles for Japanese digital terrestrial television broadcasters.[17]
Games
Since its debut in 1982, over 40 official Sokoban games have been released on various platforms, primarily in Japan but also in other regions. Most titles are standalone, though a few are sequels. The core mechanic of pushing boxes to storage locations has remained consistent in almost all official titles, with few exceptions:
One title includes stages with different core mechanics:
Ultimate Sokoban (究極の倉庫番)– features four themed stages with either strict move limits, boxes that float unless regularly touched or stored, a box that is a ghost, or boxes that, when stored, must complete an electrical circuit.[21]
Sokoban Special of Tears (涙の倉庫番スペシャル)– features a mode where the player can use tools such as ropes.[22]
Sokoban Legend: Land of Light and Darkness (倉庫番伝説 光と闇の国)– offers a story mode in which the player must push enemies into holes and push puppets onto magic circles.[23]
One title departs entirely from Sokoban:
Power Sokoban (Power倉庫番)– is an action-puzzle game that deviates from the warehouse keeper mechanic; the player shoots orbs and fills holes with rocks.[24]
The first Sokoban title was a best seller in Japan, selling over 25,000 copies by July 1984.[27][28][29] Early Sokoban titles released for several Japanese home computer systems, including the NEC PC-9801 and Sharp X1, were a hit, selling over 100,000 copies in total.[30] The Japanese Sokoban title for MSX published by ASCII sold over 400,000 copies and was considered a commercial success.[15][31] The U.S. version Soko-Ban sold over 50,000 copies by mid-September 1988.[15] In 2018, Chukyo Television Broadcasting reported that the series in total had sold over 4.1 million copies worldwide since its 1982 debut.[32]
Famicom Winning Guide in 1990 noted the Sokoban series as an established staple puzzle game, still discussed for its difficulty and depth, having been ported to multiple platforms, and continuing to be sold.[33] Reviewers frequently highlighted the games' addictive quality. Reviewing the first Sokoban, Micomgames staff stated that players would find it difficult to stop playing.[4] In 1988, Roy Wagner of Computer Gaming World suggested that anyone trying the US version, Soko-Ban, would likely remain absorbed for a prolonged period.[34]Computer Entertainer newsletter stated that playing it was fascinating and almost impossible to stop.[35] Regarding console versions, Computer and Video Games magazine staff called Sokoban for Game Boy "an infuriatingly addictive little title" and compared its addictiveness to Tetris.[36]
Commentators often highlighted one of three aspects of the game: its simplicity, the level of thinking it demanded from players, or its challenging nature. Micomgames staff, however, emphasized both simplicity and the thinking required of players, describing the first Sokoban as simple yet requiring deep thought comparable to playing Go or Shogi.[4]Family Computer magazine's All Catalog supplement described Sokoban for Game Boy as great due to the simplicity of its gameplay,[37] and Computer and Video Games magazine staff described it as one of the Game Boy's "simple but effective puzzle games."[36] Reviewers for the German magazine Happy Computer praised it as a brilliant logic puzzle that kept players thinking without pressure and recommended that players carefully observe a level before moving a box.[38] In Computer Gaming World, Wagner summarized it as "very playable and mentally challenging."[34] In Game Player's magazine, Tom R. Halfhill reviewed Shove It! for the Sega Genesis, noting it was challenging and would require players to plan their moves carefully,[39] and reviewing Boxxle for Game Boy, he stated that it required careful planning or plenty of trial and error (usually both).[40] He later commented on Boxyboy for the TurboGrafx-16 that while the initial rooms were not difficult, players would eventually encounter one that "seems impossible."[41]
The lack of variety in the series became a point of criticism. Tom R. Halfhill considered all puzzles in Shove It! essentially the same.[39] He noted that Boxxle's gameplay could become repetitive because the only variations in the screens were the number and arrangement of crates and the shape of the rooms.[40] Additionally, reviewing Boxyboy, he noted that it was "virtually identical" to Shove It! and Boxxle. He concluded that all these games required players to be content with repeatedly solving the same type of puzzle.[41]
Legacy
Because the core gameplay mechanics are not protected by intellectual property rights, many Sokobanclones have been created,[42] and the term "Sokoban," which is a registered trademark, has become genericized to describe the genre.[43] Thousands of custom Sokoban puzzles,[44] spanning a wide range of difficulty, have been created and are freely available on the internet,[45] as well as software tools, including solvers,[46] and solution optimizers.[43]
The Sokoban puzzle principle—moving objects to the correct targets by pushing them—is widespread in gaming.[47] While computers and game consoles became more powerful in the 1980s and 1990s, many games remained restricted to tile- and grid-based movement, making object-pushing puzzles a natural fit.[48] As a result, many puzzles in older titles often resembled Sokoban.[48] Some games, such as Adventures of Lolo (1989) and LIT (2009), applied the principle, and The Legend of Zelda series likewise incorporated it in its crate-moving riddles.[47][48] The principle also appeared in Resident Evil 2 (1998), which included simpler object-pushing puzzles guided by in-game hints.[48] Additionally, Sokoban-like games such as Sokomania 2 (2014) introduced further mechanics, including switches and conveyor belts.[47]
Research
The computational problem of solving Sokoban puzzles has been studied using computational complexity theory, and is known to be NP-hard[49][50] and PSPACE-complete.[51][52] Solving non-trivial Sokoban puzzles is difficult for computers because of the high branching factor (many legal pushes at each turn) and the considerable search depth (many pushes needed to reach a solution).[53][54] Even small puzzles can require lengthy solutions.[55]
Sokoban puzzles provide a challenging testbed for developing and evaluating planning techniques.[56] The first documented automated solver, Rolling Stone, was developed at the University of Alberta. It employed a conventional search algorithm enhanced with domain-specific techniques such as deadlock detection.[57][58] A later solver, Festival, introduced the FESS search algorithm and became the first automatic system to solve all ninety puzzles in the widely used XSokoban test suite.[59][60] Despite these advances, even the most sophisticated solvers cannot solve many complex puzzles that humans can solve with time and effort, using their ability to plan, recognize patterns, and reason about long-term consequences.[61][62][63]
↑"ja:倉庫番とは"[What is Sokoban]. Sokoban.jp (in Japanese). Falcon Co., Ltd. Archived from the original on September 19, 2025. Retrieved September 19, 2025.
123"ja:PART 2 脳みそを酷使するのである"[Part 2: You Will Use Your Brain to the Extreme]. MICOMGAMES (in Japanese). Vol.1, no.1. Obunsha. December 1983. p.38.
↑Soko‑Ban (Video game manual). Spectrum Holobyte. 1988. p.2.
1234"倉庫番の歴史"[The History of Sokoban]. Sokoban.jp (in Japanese). Falcon Co., Ltd. Archived from the original on September 17, 2025. Retrieved September 17, 2025.
↑"Sokoban Official Site". Sokoban.jp (in Japanese). Falcon Co., Ltd. Archived from the original on November 17, 2025. Retrieved November 17, 2025.
↑"ja:Puzzle GAMES! – 倉庫番伝説・光と闇の国"[Puzzle GAMES! – Sokoban Legend: Land of Light and Darkness] (in Japanese). Archived from the original on November 4, 2025. Retrieved November 4, 2025.
↑"ja:POWER 倉庫番"[Power Sokoban]. Nintendo (in Japanese). Archived from the original on November 3, 2025. Retrieved November 3, 2025.
↑Several efficient Sokoban solvers aim to find short, but not necessarily optimal, solutions, including JSoko, YASS, and Takaken. Balyo, Tomáš; Froleyks, Nils (2022). "AI Assisted Design of Sokoban Puzzles Using Automated Planning". In Wölfel, Matthias; Bernhardt, Johannes; Thiel, Sonja (eds.). ArtsIT, Interactivity and Game Creation. Springer. pp.429–430. doi:10.1007/978-3-030-95531-1_29. ISBN978-3-030-95531-1.
↑Joseph C. Culberson (1997). "Sokoban is PSPACE-complete"(PDF). Technical Report TR 97-02, Dept. Of Computing Science, University of Alberta. Archived from the original(PDF) on May 28, 2024.
↑Robert Aubrey Hearn (2006). Games, Puzzles, and Computation(PDF) (PhD thesis). Massachusetts Institute of Technology. pp.98–100. Archived from the original(PDF) on October 11, 2025. Retrieved October 11, 2025.
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