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How Math Broke Connect 4
A mathematician found a way to guarantee a win
Connect 4 is a staple game. It’s easy to learn, and a really fun challenge for two players. Part of its appeal is how simple the rules are. Each play selects a color and takes turns dropping chips onto the board. Because of the way the board is set up, the chip always falls into the bottom-most available space in whatever column they are placed in. This takes place on a 7x6 board, and each spot can hold one chip. The first player to get four chips of their color in a line (diagonals count too) is the winner.
This is one of those games that has more going on than first meets the eye. As you can imagine, strategies for Connect 4 become quite complex. Connect 4 is an example of a game with perfect information. This means that both players have the same amount of knowledge at all times. During a game of Connect 4, there are no hidden facts other than what your opponent is planning. Other games with perfect information are Chess and Checkers, while some games without it are Poker or Stratego.
Connect 4 has a massive amount of different board states, over 4.5 trillion! This has limited the ability of computers to come up with optimal strategies. However, some clever tricks and advances in computing power have been able to overcome this limitation.