Connect Four (also known as Connect 4, Four Up, Plot Four, Find Four, Captain's Mistress, Four in a Row, Drop Four, and Gravitrips in the Soviet Union) is a game in which the players choose a color and then take turns dropping colored tokens into a six-row, seven-column vertically suspended grid.

The game was created by Howard Wexler, and first sold under the Connect Four trademark[10] by Milton Bradley in February 1974.

Connect Four also belongs to the classification of an adversarial, zero-sum game, since a player's advantage is an opponent's disadvantage.

For classic Connect Four played on a 7-column-wide, 6-row-high grid, there are 4,531,985,219,092 (about 4.5 trillion) positions[12] for all game boards populated with 0 to 42 pieces.

Connect Four has since been solved with brute-force methods, beginning with John Tromp's work in compiling an 8-ply database.

[13][17] The artificial intelligence algorithms able to strongly solve Connect Four are minimax or negamax, with optimizations that include alpha-beta pruning, move ordering, and transposition tables.

The code for solving Connect Four with these methods is also the basis for the Fhourstones[18] integer performance benchmark.

With perfect play, the first player can force a win,[13][14][15] on or before the 41st move[19] by starting in the middle column.

[21] Several versions of Hasbro's Connect Four physical gameboard make it easy to remove game pieces from the bottom one at a time.

Gameplay works by players taking turns removing a disc of one's own color through the bottom of the board.

If it was not part of a "connect four", then it must be placed back on the board through a slot at the top into any open space in an alternate column (whenever possible) and the turn ends, switching to the other player.

The Five-in-a-Row variation for Connect Four is a game played on a 6 high, 9 wide grid.

The game plays similarly to the original Connect Four, except players must now get five pieces in a row to win.

Connect Four was released for the Microvision video game console in 1979, developed by Robert Hoffberg.

Instead of the usual grid, the game features a board to place colored discs on.

Just like standard Connect Four, the object of the game is to try get four in a row of a specific color of discs.