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
Only Connect wall, the missing groupings are shown. Teams can then earn 1 point per group for identifying the connection, regardless of whether they correctly identified the grouping. A team that identifies all four groups and all four connections earns a 2-point bonus, for a total of 10 points. Unlike the previous two rounds, teams have no opportunity to score on their opponents' wall. On 1 March 2010, an interactive online version of this round was put on the Only Connect website. Since mid-2011, coinciding with series 5, the website took online submissions for new Connecting Walls, although a successful submission does