Rubik's Brain Game is more or less a 2-dimensional Mastermind. As in that game, players take turns setting up a pattern which the other player must deduce, with the player making the deduction in the fewest moves winning the game.
In this game, a pattern is a 3x3 grid with each square being one of 6 colors, looking much like the side of a scrambled Rubik's Cube (the pattern is formed with 9 small cubes). On each turn, the guesser can either ask the setter if a given set of three colors are in a given row or column, or can ask if a given space is a specific color. In the former case the colors present and the colors not present are placed in different sections of the board for tracking purposes.