Four in a row rules

Two players take turns dropping discs into a seven-column, six-row board. Amber starts. Each disc lands in the lowest free space in its column.

Make a line of four

Four discs of your color win horizontally, vertically or along either diagonal. The round stops as soon as a player connects four. A full board with no winning line is a draw.

A first threat to watch

Three adjacent discs are a threat when an empty space beside them can receive the fourth. A gap high above the next landing space cannot be filled on this turn. Check where your disc will actually land.

Play against the computer

You play amber. The computer plays teal and moves after you. It takes an immediate win when available and blocks a single immediate winning threat. Undo turn removes your latest move and the computer’s reply. If the computer is still thinking, Undo removes only your move.

Share the screen

Choose Two players. Amber and teal alternate. Undo turn removes one disc. Both modes have separate saved rounds, so changing mode preserves the other round.

Keyboard and touch

Tap a numbered column button to drop a disc. Use the left and right arrow keys to choose a column, then Enter or Space to drop. Home and End choose the first or last column. Number keys 1–7 work when a column button has focus.

Play again

New game clears this mode’s round after confirmation. Other modes keep their saved round.

Fourfold is an original browser implementation of the classic four-in-a-row mechanism. Hasbro’s classic Connect 4 instructions were used to check rule facts. This site is independent and does not use their board art, logo or published diagrams.