Thinking Rabbit was never one of the largest companies in the Japanese video game industry. It did not have the enormous development staffs, arcade divisions, or worldwide marketing operations that would later define companies such as Nintendo, Sega, Namco, or Capcom. Instead, the company emerged from the much smaller world of Japan’s early personal computer industry, when an individual programmer with an idea could still duplicate cassette tapes, package software, and sell games almost by hand.
From that modest beginning came one of the most enduring puzzle designs in video game history.
Thinking Rabbit is remembered above all as the company behind Sokoban, the deceptively simple warehouse puzzle created by Hiroyuki Imabayashi. Yet reducing Thinking Rabbit to Sokoban alone misses much of its history. During the 1980s and 1990s, the company produced puzzle games, graphical murder mysteries, adventure games, computer ports, console software, and subcontracted development work. Its staff also became part of a wider network of Japanese developers whose careers continued long after Thinking Rabbit itself became inactive.
The company’s history is unusually well documented because Imabayashi was interviewed while Thinking Rabbit was still young. A December 1983 issue of LOGiN magazine captured him discussing the company, its games, and his philosophy when Thinking Rabbit employed only a handful of people. Later recollections by Imabayashi, surviving company material, original software, advertisements, and preservation records allow much of that story to be reconstructed.
Even so, one important problem remains. The exact chronology of Thinking Rabbit’s beginning is not perfectly clear. The modern official Sokoban site says Imabayashi formed Thinking Rabbit and released Sokoban in 1982, with its historical product list dating several computer versions to December of that year. The 1983 LOGiN interview, however, described Thinking Rabbit as having been established only about six months earlier and referred to Sokoban as a May release. Preservation records sometimes give still other dates for particular versions. The surviving evidence therefore supports a clear general sequence, but not a perfectly settled month-by-month chronology.
Hiroyuki Imabayashi Discovers the Computer
Thinking Rabbit began with Hiroyuki Imabayashi, a man who did not originally plan to become a professional game developer.
In the 1983 LOGiN interview, Imabayashi remembered that a friend had brought a Sharp MZ computer to his home several years earlier. The machine was heavy enough that the friend left it behind rather than immediately carrying it home again. Imabayashi, who knew almost nothing about computers, became fascinated. He spent roughly three days absorbed in the machine and its manual, eventually producing a simple game involving a parachuting character attempting to land at particular coordinates.
The experience convinced him to buy an NEC PC-8001 of his own. He subsequently created several games for the machine, not as commercial products, but because programming had become a new hobby.
Imabayashi later remembered Sokoban itself beginning in the spring of 1981. He had been thinking about a character pushing objects and constructed the concept in BASIC as a puzzle. The important idea was that the objects the player needed to put away would themselves interfere with the process of putting everything away. A box pushed into the wrong location could become impossible to retrieve, transforming an apparently simple movement problem into a game of planning several moves ahead.
Years later, Imabayashi identified Hudson’s Aldebaran as an influence on the idea. In that game, movable objects could be pushed and used as protection. Imabayashi took the act of pushing an object and separated it from the action game surrounding it, making the movement itself the basis of a puzzle. He also rejected a later story that Sokoban had originated from a computer game competition, explaining that the prototype had simply been a personal hobby project.
The earliest version was extremely plain. According to the 1983 interview, the prototype used basic characters such as circles, squares, and Xs rather than elaborate graphics. Imabayashi invited friends to his house and watched them struggle through the puzzles. That reaction became part of the pleasure of designing them. He was not merely writing a program. He was constructing problems for other people to untangle.
From Hobby Project to Sokoban
The transition from hobby to business came almost accidentally.
Imabayashi’s wife’s family operated a record store, and a small computer section was eventually established there. A PC-8801 gave Imabayashi a platform on which he could improve the game, replace the crude prototype presentation with graphics, and expand it into a commercial-looking product.
He later recalled that someone connected to software distribution saw the game and told him it could sell. That encouragement changed his plans. Imabayashi purchased dubbing equipment and began preparing Sokoban for sale. The modern official account says that Thinking Rabbit was created in 1982 for that purpose.
The mechanics required almost no explanation. The player moved through a warehouse and pushed pieces of luggage or boxes onto designated storage locations. A box could be pushed but not pulled. Two boxes could not simply be shoved together down a corridor. If a box entered a corner that was not a destination, the puzzle might be ruined.
That inability to reverse every action gave Sokoban its depth. Each push potentially altered the future of the entire puzzle.
The simplicity of the program was something Imabayashi freely acknowledged. He even told LOGiN that he did not consider himself an exceptional programmer. What mattered to him was the idea. In his view, sophisticated technology could be acquired, but an interesting concept had to be imagined. Decades later, he summarized the early Thinking Rabbit philosophy in similar terms. Because the young team could not compete through highly advanced programming, it could compete through games that required thought, particularly puzzles and adventures.
That philosophy explains the company’s name surprisingly well. Imabayashi remembered sketching a rabbit mascot in the margins of a notebook. He created the rough form of the logo himself and had a designer friend finish it. The rabbit became attached to the company, while the word “Thinking” reflected the sort of games in which he believed the small team could distinguish itself.
Building Thinking Rabbit in Takarazuka
Thinking Rabbit operated from Takarazuka in Hyogo Prefecture rather than one of the better-known centers of Japan’s technology industry. In 1983, LOGiN described it as a tiny and unconventional operation.
There were five people associated with the company, including Imabayashi. Their abilities included assembly programming, hardware knowledge, programming, and design. They were also friends, many of whom had other careers and worked on Thinking Rabbit projects from their homes. Saturday nights became opportunities to gather, exchange ideas, and continue working into the early morning.
The first Sokoban was similarly handmade. Surviving photographs published with the LOGiN interview show cassette tapes that Imabayashi duplicated and packaged himself. He designed the stages on graph paper before entering them into the program. The commercial game contained twenty stages, but creating those stages proved more difficult than writing the underlying game system.
That distinction became central to Sokoban’s future. The program could be simple while the puzzles could be almost endlessly complicated.
Imabayashi later remembered that numerous proposed stages were discarded during experimentation. Ten additional puzzles appeared in PC Magazine in 1983 at the magazine’s request, demonstrating how easily the basic system could support new collections.
The original game also contained unusual breakable or passable walls in later stages. Imabayashi eventually recognized that such tricks weakened the purity of the puzzle. Some players apparently objected that discovering a hidden gimmick was different from logically solving a warehouse problem, and the mechanic disappeared from later versions.
When Players Became Puzzle Designers
Thinking Rabbit soon found a way to turn its audience into part of the development process.
Players who completed the original game’s twenty stages could submit their own puzzle designs. At the time, this could mean literally drawing a proposed level on graph paper and sending it to the company. Strong submissions could be selected for future releases.
That idea became particularly important for Sokoban 2. Contemporary advertising announced the sequel late in 1983, and the new game expanded the collection to fifty stages. It also introduced a stage editor, allowing players to build puzzles directly rather than relying only on paper. Some of the problems incorporated into the sequel came from players around Japan.
It was an unusually participatory model for an early 1980s computer game. Thinking Rabbit had created the rules, but the rules were flexible enough that an entire community could create new content within them.
The same spirit appeared elsewhere. Imabayashi later explained that T.N.T. Bomb Bomb, another Thinking Rabbit puzzle title, began with an idea submitted by a Sokoban fan. He purchased the concept and turned it into a commercial product.
Meanwhile, Sokoban spread across Japanese computer platforms. Thinking Rabbit’s official history records releases for systems including the PC-8801, FM-7, PC-8001mkII, X1, MZ-2000 and PC-6001 families, followed by numerous versions of Sokoban 2. ASCII published MSX editions, and other companies eventually brought the design to game hardware far removed from the computers for which Imabayashi had originally written it.
Thinking Rabbit Enters the Murder Mystery
Success did not turn Thinking Rabbit into a company devoted exclusively to warehouse puzzles.
By 1983, it was already moving into graphical adventure games with Kagiana Satsujin Jiken, usually translated as The Keyhole Murder Case. The game placed the player inside a murder mystery involving a locked room, suspects, physical evidence, hidden passages, and interrogation.
The title reflected Imabayashi’s interest in novels and Western computer adventures. In his contemporary interview, he discussed games such as Wizard and the Princess and Cranston Manor, while preservation research also connects Kagiana Satsujin Jiken to the mystery structure of Deadline and the exploration of Mystery House.
Imabayashi originally wanted an extensive conversational system that would allow the player to interrogate suspects more freely. Memory limitations made the idea difficult to implement, so he devoted more of the available space to graphics. The 1983 interview said the finished game contained more than eighty images, an impressive emphasis on visuals at a time when text-heavy adventures remained common.
The player was not simply searching a house for treasure. Evidence had to be discovered, suspects questioned, relationships uncovered, and a murder explained. The Game Preservation Society has called it an important early example of the Japanese mystery adventure and noted that the combination of exploration and interrogation distinguished it from a straightforward imitation of existing adventures.
Thinking Rabbit continued developing this side of its identity. In the 1983 interview, Imabayashi was already discussing Doukeshi Satsujin Jiken, or The Clown Murder Case, which he envisioned with roughly 150 images and a final challenge requiring the player to identify the murderer and weapon. He also described a more elaborate science fiction, romance, and mystery scenario involving time travel. That project eventually appeared as Casablanca ni Ai o: Satsujin-sha wa Jikuu o Koete.
These games reveal what Thinking Rabbit actually meant as a development company. Sokoban and the murder mysteries looked very different on the screen, but both were built around thinking, experimentation, deduction, and the satisfaction of reaching an answer.
From Japanese Computers to the Wider Game Industry
Sokoban continued expanding even as Thinking Rabbit pursued other projects.
ASCII and other publishers brought the game to additional platforms, and by 1986 Namida no Sokoban Special had appeared for Nintendo’s Famicom Disk System with 150 puzzle stages, a level editor, and additional game mechanics. Later releases included Sokoban Perfect, Sokoban Revenge, Super Sokoban, and versions for still more computers and consoles.
The series also moved beyond Japan. In 1988, Spectrum HoloByte released Soko-Ban in the United States for systems including the IBM PC, Commodore 64, and Apple II. Imabayashi later confirmed that he had granted Spectrum HoloByte the rights for its localized version.
American computer magazines treated the game as something unusual in a market crowded with action, simulation, and adventure software. Compute! described fifty warehouse puzzles and highlighted the game’s level editor, while Computer Gaming World reviewed Soko-Ban alongside Tetris, placing two imported puzzle designs before an American audience that was becoming increasingly receptive to games built around simple rules and deep problem solving.
Thinking Rabbit itself also became connected to a much broader network of Japanese development. Research by the Game Developer Research Institute traces the company through partnerships such as Trinity, the Disk Original Group, and Scap Trust, along with work spanning computers, the Famicom, Mega Drive, Super Famicom, 3DO, Saturn, and PlayStation. Some individual credits and subcontracting relationships remain uncertain, which is common when reconstructing Japanese game development from this period, but the surviving evidence shows that Thinking Rabbit’s activities reached well beyond the software carrying its own name on the box.
The company also became a starting point for developers who later established or joined other studios. GDRI research records former Thinking Rabbit programmers associated with companies such as Dragnet, Giraffe Soft, and Flight-Plan. That movement of personnel helped spread the experience accumulated in Takarazuka into other parts of the Japanese game industry.
The Rabbit Becomes Quiet
By the late 1990s, Thinking Rabbit’s role had changed considerably.
Sokoban had grown larger than the company that created it. Different publishers and developers could license the game and produce versions for new hardware without Thinking Rabbit performing every conversion itself. The puzzle had effectively become a format, a set of rules capable of surviving technological generations almost unchanged.
Imabayashi later said that Thinking Rabbit ceased active work around 2000. He described the legal company as remaining in existence but inactive, with the Thinking Rabbit name continuing primarily as a brand. He also explained that his rights were being managed through Falcon.
The modern official Sokoban site likewise identifies Falcon in connection with the trademarks and rights surrounding Sokoban and Thinking Rabbit, while continuing to credit Hiroyuki Imabayashi as the original creator. In 2015, Imabayashi wrote that the game was being renewed with help from longtime fans and Falcon more than three decades after its creation.
That longevity would have been difficult to predict when the first levels were being drawn on graph paper.
The Legacy of Thinking Rabbit
Thinking Rabbit occupies an unusual place in video game history because its greatest achievement was not technological spectacle. It was the discovery that a tiny number of rules could produce an enormous number of meaningful decisions.
Imabayashi openly admitted that Sokoban was simple to program. That simplicity was not a weakness. It allowed the game to move from one computer architecture to another while preserving the thing that mattered most: the puzzle.
The same philosophy shaped the young company around it. Thinking Rabbit’s developers knew they could not necessarily defeat larger competitors through technical sophistication, so they placed their confidence in ideas. A warehouse in which boxes could only be pushed became a worldwide puzzle. A locked-room murder became an excuse to experiment with graphics, evidence, and interrogation. Players were invited to become designers, while submitted concepts could become new commercial games.
From a few friends working in and around Takarazuka, Thinking Rabbit developed a body of software that touched Japanese personal computers, Nintendo hardware, Sega systems, Western computer markets, and later generations of consoles. Its company name eventually faded from active development, but its best idea never did.
More than forty years after the first BASIC prototype, Sokoban remains immediately understandable. A player stands in a room. Boxes must be moved to their destinations. They can be pushed but never pulled.
Everything that follows comes from thinking.
Sources & Further Reading
Imabayashi, Hiroyuki. “ごあいさつ [Greeting].” Sokoban Official Site. Falcon Co., Ltd. Accessed October 13, 2026. https://www.sokoban.jp/greeting.html
Thinking Rabbit and Falcon Co., Ltd. “倉庫番の歴史 [History of Sokoban].” Sokoban Official Site. Accessed October 13, 2026. https://www.sokoban.jp/history.html
Thinking Rabbit. Thinking Rabbit Official Site. Accessed October 13, 2026. https://thinkingrabbit.jp/
“考えるウサギはパソコンの野を駆ける! [The Thinking Rabbit Runs Through the Fields of the Computer!].” LOGiN, December 1983, 136–139. Internet Archive. https://archive.org/details/login-magazine-dec-1983-thinking-rabbit
“Thinking Rabbit: 1983 Developer Interview.” Translated from LOGiN, December 1983. Shmuplations, March 30, 2022. https://shmuplations.com/thinkingrabbit/
Montiers Aguilera, Carlos. “My Conversation with Mr Hiroyuki Imabayashi.” Sokoboxes, May 22, 2022. Based on conversations beginning in October 2020. https://sokoboxes.com/articles/my-conversation-with-mr-hiroyuki-imabayashi/
Tanaka, Junji, Hiroyuki Imabayashi, and Masami Ishii. THE 倉庫番 [The Sokoban]. SCALE, 1986. ISBN 4-88239-606-8. https://archive.org/details/sokoban-book
“倉庫番[番外編] [Sokoban Extra Edition].” PC Magazine, August 1983, 52–53. Internet Archive. https://archive.org/details/pc-magazine-aug-1983-sokoban-extra-edition
“倉庫番2 [Sokoban 2].” LOGiN, July 1985, 76. ASCII Corporation. Internet Archive. https://archive.org/details/logi-n-july-1985
Takahashi, Pyonta. “第13回 シンプル is パーフェクト──倉庫番 [No. 13: Simple Is Perfect: Sokoban].” BEEP, February 12, 2025. https://www.beep-shop.com/column_entry/67956/
Game Preservation Society. “シンキングラビット / Thinking Rabbit.” PC-8801 Game Library. Accessed October 13, 2026. https://www.gamepres.org/pc88/library/thinking.htm
Game Preservation Society. “倉庫番 [Sokoban].” PC-8801 Game Library. Accessed October 13, 2026. https://www.gamepres.org/pc88/library/1983/soko.htm
Game Preservation Society. “鍵穴殺人事件 [Kagiana Satsujin Jiken].” PC-8801 Game Library. Accessed October 13, 2026. https://www.gamepres.org/pc88/library/1983/kagiana.htm
Game Preservation Society. “鍵穴殺人事件 [Kagiana Satsujin Jiken].” Game Preservation Society Software Catalog. Accessed October 13, 2026. https://www.gamepres.org/catalog/?cat=1&id=8811008515005&nav=brand
Game Preservation Society. “道化師殺人事件 [Doukeshi Satsujin Jiken].” Game Preservation Society Software Catalog. Accessed October 13, 2026. https://www.gamepres.org/catalog/?cat=1&id=8811002745002&nav=brand
Game Developer Research Institute. “Thinking Rabbit.” Accessed October 13, 2026. https://gdri.smspower.org/wiki/index.php/Thinking_Rabbit
Game Developer Research Institute. “Thinking Rabbit (Credits).” Accessed October 13, 2026. https://gdri.smspower.org/wiki/index.php/Thinking_Rabbit_(credits)
Agency for Cultural Affairs, Japan. 平成25年度メディア芸術デジタルアーカイブ事業 [FY2013 Media Arts Digital Archive Project]. Tokyo: Agency for Cultural Affairs. https://macc.bunka.go.jp/wp-content/uploads/2023/01/4e3266f8d6bee26c3ec24567591ca347.pdf
Wagner, Roy. “Puzzling Encounters: Two Titles from Spectrum HoloByte’s International Series.” Computer Gaming World, no. 47, May 1988, 42–43. https://www.cgwmuseum.org/galleries/issues/cgw_47.pdf
Wierda, Brian. “Soko-Ban.” Compute!, vol. 10, no. 6, issue 97, June 1988. Internet Archive. https://archive.org/details/1988-JUn-compute-magazine
Lesser, Hartley, Patricia Lesser, and Kirk Lesser. “The Role of Computers.” Dragon, no. 132, April 1988, 80–85. https://archive.org/details/DragonMagazine260_201801/DragonMagazine132
Low, Lafe. “News Line: Made in Japan.” inCider, no. 43, November 1988, 14–15. https://archive.org/search?query=incider+november+1988
Kaneko, Yoichi, ed. パソコンゲーム80年代記: パソコンゲームの進化を一望する [PC Games: Chronicle of the 1980s]. Tokyo: Tatsumi Publishing, 1990. https://ndlsearch.ndl.go.jp/books/R100000002-I032059652
Kaneko, Yoichi, ed. パソコンゲーム80年代記 [PC Games: Chronicle of the 1980s]. Tokyo: Tatsumi Publishing, 1990. Internet Archive. https://archive.org/details/pcgame80
テレビゲーム: 電視遊戯大全 [Video Games: Complete Collection of TV Games]. Television Game Museum Project. 1988. https://archive.org/details/tv-games
Sasaki, Jun. レジェンドパソコンゲーム80年代記 [Legend PC Games: Chronicle of the 1980s]. 2015. https://ci.nii.ac.jp/ncid/BC12991421
MobyGames. “Thinking Rabbit Inc.” Accessed October 13, 2026. https://www.mobygames.com/company/2765/thinking-rabbit-inc/