Connect Four

Connect Four is a deceptively simple strategy game: drop a disc into a column, and the first player to line up four in a row — horizontally, vertically or diagonally — wins.

This version runs a minimax search four moves deep, which means the CPU will block your obvious threats and build its own. Beating it requires setting up two threats at once, so it can only block one.

The scoreboard tracks wins, losses and draws for the session. Games last a minute or two, and the board is small enough to read at a glance.

How to play Connect Four

• Click a column to drop your red disc into the lowest empty slot.
• The CPU answers with a yellow disc.
• Line up four of your discs in any direction to win.
• If the board fills without a line, the game is a draw.

Tips & strategy

Connect Four is about creating two threats at once. A single threat is always blocked; a double threat is not.

• Control the centre column. More winning lines pass through it than any other column.
• Look for moves that create two separate three-in-a-rows — the CPU can only block one.
• Block the CPU's three-in-a-row immediately, but check whether blocking gives it a better position elsewhere.
• Play the bottom row early. Discs there support vertical and diagonal lines later.
• Avoid stacking directly under the CPU's threats; it gives them a free extension.
• When the board is crowded, count the remaining columns — forcing the CPU into an edge column limits its options.

Controls

Questions