Connect Four
Drop four discs in a row — horizontally, vertically or diagonally — against the computer or a friend.
Click any column or press 1–7 (or ← → + Space) to drop a disc · Z to undo
How to Play Connect Four in 3 Steps
Choose 1P or 2 Players
Play against the built-in minimax computer (Easy, Medium or Hard) or switch to 2 Players to share the screen.
Drop a disc
Click any of the 7 columns — or press keys 1–7 — to drop your disc into the lowest open slot of that column.
Connect four in any direction
The first player to line up four discs horizontally, vertically or diagonally wins; the winning four are highlighted.
Controls & rules
| Action | Keyboard | Mouse / Touch |
|---|---|---|
| Drop in column 1–7 | 1–7 | Click / tap any cell in that column |
| Aim & drop | ← → then Space / Enter | — |
| Undo last turn | Z | Tap Undo |
| New game | Space (when finished) | Tap New game |
Connect Four — Frequently Asked Questions
How strong is the Hard computer?
Hard searches 7 plies ahead using alpha–beta pruning with centre-column move ordering and threat evaluation. It spots forced four-in-a-row traps several moves early while still replying in a few milliseconds.
Why is the centre column so important?
Any horizontal or diagonal four-in-a-row spanning the board has to pass through the middle column (column 4), so controlling it gives you the most winning lines.
What does Undo take back in 1P mode?
Both the computer’s reply and your last disc, returning the board to your previous turn.
How do I clear the win/draw tally?
Press Reset in the toolbar (or Esc) to wipe stored scores and restore default options.
Is anything uploaded or tracked while I play?
No. The game runs entirely in your browser tab. Your best score or win tally is saved only in your browser’s localStorage and cleared when you press Reset.