Connect Four on 6 high, 7 wide grid, there are 4,531,985,219,092 positions for all game boards populated with 0 to 42 pieces. The game was first solved by James Dow Allen (October 1, 1988), and independently by Victor Allis (October 16, 1988). Allis describes a knowledge-based approach, with nine strategies, as a solution for Connect Four. Allen also describes winning strategies in his analysis of the game. At the time of the initial solutions for Connect Four, brute-force analysis was not deemed feasible given the game's complexity and the computer technology available at the time. Connect Four has since been solved with
Inner Circle (board game) Inner Circle (board game) Inner Circle is a board game for 2–4 players first published in 1981 by Milton Bradley and designed by Virginia Charves and Wayne J. Yee. Inner Circle uses a modular, four-level board design. Each level is hexagonal, with holes (referred to in the game as "survival spots") that allow playing pieces to pass from the current level to the next. Each level is marked with circular spaces with between 1–4 dots inside the circle that determine how many spaces that piece may move. Each successive level is smaller than the previous level (stacked on top of