Abaku Sets World Record as Longest-Running Online Multiplayer Arithmetic Game With a Shared Game State
Updated: Sep 4
The Czech educational game has remained publicly available online since May 18, 2009, surviving multiple platforms and generations of web technology while preserving its distinctive shared mathematical playing field.
By Atlas Editorial Team
3 September 2026 • Prague [Czech Republic]
More than two decades ago, Czech educator Vladimír Tesař began experimenting with a simple idea: what if people could learn to “read” numbers the way they read words?
He would see a number such as 246 and instinctively recognize the relationship 2 + 4 = 6. Over time, those spontaneous connections led him to wonder whether arithmetic could be taught less as a sequence of exercises and more as a language of relationships — and whether a game might be the best way to make that happen.
From “Reading Numbers” to a New Kind of Game
Those experiments eventually became Abaku, a mathematical strategy game in which players create valid arithmetic relationships using numbered tiles. The mathematical operators are not printed on the board. Players must recognize the relationships themselves. A sequence such as 1, 2, 3 can represent 1 + 2 = 3, while 1, 2, 3, 4 might be read as 12 ÷ 3 = 4.
On May 18, 2009, Abaku made its documented public online premiere. A contemporary Czech technology announcement described the game as an online experience for two to four players and identified Geewa as the developer of the electronic version. That launch began a public online history that has now survived multiple platforms, developers and generations of web technology.
Atlas World Records has certified Abaku for the Longest-running publicly available online multiplayer arithmetic game with a shared game state.
The wording of the record reflects an important distinction in how Abaku works.
Many multiplayer mathematics products allow players to compete simultaneously while effectively solving problems in parallel. Abaku instead places its players inside one shared mathematical environment. Every move changes the position faced by the next player, affecting what can be created, what opportunities remain and what strategic possibilities emerge.
“I did not want two people simply solving arithmetic problems alongside each other and then comparing results,” Tesař explained. “In a game, what one player does matters to the other.”
“In Abaku, each move changes the arithmetic environment in which the next player will play. Mathematics is not the test. It is the means by which the game is played.”
That structure also means that being quick at arithmetic is not enough to master the game. Tesař compares the learning process to reading. A beginner sees individual letters; an experienced reader recognizes complete words. In Abaku, experienced players begin to recognize several mathematical relationships simultaneously and use them strategically — deciding not only what to create, but what possibilities a move may leave for an opponent.
The game’s early audience was broad. Abaku appeared on Hry.cz, then one of the Czech Republic’s major online gaming portals, where children, adults and retirees could encounter it alongside conventional games. Tesař remembers its audience growing gradually rather than exploding overnight, with players often remaining loyal for years.
That longevity became increasingly significant as the technology underneath the game changed.
Seventeen Years of Online Evolution
That longevity became increasingly significant as the technology underneath the game changed.
The original electronic Abaku passed through the Geewa and Hry.cz environments before the Hry.cz online-game service moved to Duelovky.cz in 2015. A later generation of ABAKU PLAY developed by Qest launched on December 10, 2020, shortly before Adobe ended support for Flash Player. Qest later described its application as the fifth version of Abaku, reinforcing the continuity of the game across successive technological implementations.
The most recent major transition came in January 2026. Technical correspondence reviewed by Atlas documents the deployment of a successor ABAKU PLAY implementation, followed by a period in which users were reaching both the outgoing and new systems. Qest subsequently confirmed that the legacy implementation had been switched off on January 27, 2026.
The code changed. The servers changed. The interfaces changed. But the game itself remained recognizable.
“It is still the same game,” Tesař said. “The technology has changed. Abaku has remained Abaku.”
That distinction became central to the Atlas adjudication. The record does not depend on one uninterrupted server, one software codebase, one domain name or the continuous existence of the same user accounts. Instead, Atlas examined whether the same identifiable game remained publicly available through a documented lineage of successor implementations while preserving its defining gameplay structure. The historical and current evidence shows the same essential model: players share a common board, place numbers into an evolving position and create arithmetic relationships that affect subsequent play.
The record was also subjected to comparative research beyond Abaku’s own history. Earlier online mathematics products were identified, including Live Mathletics, while Tux Math Scrabble emerged as an important mechanical predecessor because of its arithmetic tile-construction format. Atlas’s research did not establish an earlier publicly available online multiplayer arithmetic game with the same shared-game-state structure and a longer documented running history than Abaku.
For Tesař, however, the record is secondary to the educational idea that produced the game in the first place.
Abaku did not begin as entertainment that later found a classroom application. Education came first.
“It is the primary branch of Abaku,” he said. “Abaku did not begin as a game that we later discovered could also be used in education. The educational idea came first, and the game developed from it.”
That mission has required a larger community than one inventor could sustain alone. Tesař credits developers, educators, players, helpers and sponsors with carrying Abaku across changing technologies and keeping the project alive.
“I am only one cog in a machine made up of people from many different professions who take care of Abaku,” he said.
The Record Is Not the Goal
When Tesař first began moving numbers around on paper around the year 2000, he did not know where the idea would lead. Within several years, however, he had become convinced that it was worth pursuing — and that meaningful adoption would require patience.
“I knew that if Abaku was going to succeed, it would not happen in a year or two,” he said. “I expected it to take ten or twenty years.”
More than 17 years after its public online premiere, people are still playing.
For Tesař, the Atlas World Records certification is not an endpoint.
“The record is not the goal,” he said. “If it helps more people discover Abaku, it has served its purpose.” You can find Abaku online here: https://abakuplay.com/
His long-term ambition remains the same one that began the project more than two decades ago: for Abaku to become a standard method for teaching arithmetic, not only in the Czech Republic, but internationally.
The technology will continue to change.
The game will continue to develop.
The goal, Tesař says, remains the same.
Certified by Atlas World Records on 1 September 2026