for iOS and Android
Notakto - Counterwave Get it on Google Play
Notakto is a two-player game that is similar to Tic-Tac-Toe, except that both players make X's, and whoever completes three-in-a-row LOSES the game.
One-board notakto game, in progress
One-board Notakto game, in progress
For a challenge, play a multiboard game of Notakto. On your move, make an X on just ONE of the boards. The computer may respond on the board you played on, or on some other board. A board that already has a three-in-a-row configuration is considered out of play. To win, force the computer to complete the last three-in-a-row configuration on the last available board still in play.
Three-board notakto game, in progress
Three-board Notakto game, in progress
Choose the Rated play option and work toward becoming a Notakto World Champion. Winning games at higher levels of difficulty on multiple boards will increase your rating faster.
Rated Notakto play
Rated play of Notakto
Learn more about Notakto on the Numberphile YouTube channel: Or read the complete mathematical theory of the game here: Do you have a question about Notakto? Send email to