Connect Four
Drop your discs and line up four in a row — across, down or diagonally — against a computer that ranges from easy to tough, or with a friend on the same screen.
At a glance
- The classic 7-column, 6-row board, plus larger 8×7 and 9×7 boards for a longer game.
- Play the computer on Easy, Medium or Hard, or a friend taking turns on the same phone, tablet or computer.
- Hard searches many moves ahead — with alpha-beta pruning and a transposition table — for up to a second per move and never misses a win or a block it can see.
- Connect Four is a solved game: with perfect play the first player wins by starting in the centre column, at the latest on the 41st move. James D. Allen and Victor Allis proved it independently in October 1988.
- The 7×6 board has 4,531,985,219,092 possible positions.
- Hints, undo, sound, full screen and keyboard play (keys 1–7 drop a disc); scores are kept on your device. Free, with no download or sign-up.
Step by step
How to play Connect Four
- 1
Pick an opponent
Choose Computer and a difficulty, and your colour — Red moves first — or A friend to play on the same device.
- 2
Drop a disc
Tap a column (or press its number). The disc falls to the lowest free space.
- 3
Make four in a row
Line up four of your discs across, down or diagonally before your opponent does. A full board with no line is a draw.
- 4
Play again
Press Play again — the score keeps adding up. Use Hint or Undo while you learn.
Features
Everything you need, nothing you don’t
An opponent for everyone
Easy for children, Medium for a fair game and Hard for a real challenge — it blocks threats and sets up its own.
Two players, one screen
Pass the phone or share the keyboard, with your own names and a running score.
Learn the tricks
Ask for a hint to see the strongest column — it tells you when a forced win is on the board.
Fair starts
Turn on “Take turns going first” so the first move swaps every game — going first is a real advantage.
Bigger boards
Try 8×7 or 9×7 for more room to build threats.
Plays anywhere
Phones, tablets and computers, with keyboard control and screen-reader announcements of every move.
Connect Four strategy
- Take the centre. The middle column is part of more possible lines than any other — that is why perfect play starts there.
- Block threes at once. If your opponent has three in a row with an empty square they can reach, drop there before anything else.
- Build double threats. Two winning squares at the same time can’t both be blocked — the most common way games are won.
- Watch the square below. Don’t fill the space directly under your opponent’s winning square: your disc lets theirs land on it.
- Think in rows. The first player usually wants threats on odd rows (counting from the bottom), the second player on even rows — a key idea in Victor Allis’s solution.
How the computer plays
The computer reads the board column by column, tries the centre first and looks ahead with a minimax search pruned by alpha-beta, remembering positions it has already scored. When it can’t see to the end of the game it scores the board by the open lines each side still has. Hard thinks for up to a second and often looks ten or more moves ahead; it is strong, but it is not a perfect solver — a well-built trap can still beat it.
FAQ
Frequently asked questions
Who wins Connect Four with perfect play?
How many positions are there in Connect Four?
Can I play against a friend?
Is the Hard level unbeatable?
Can I take back a move?
Does it work offline?
Keep going
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