How to Play Connect 4
Connect 4 is a two-player connection game played on a vertical 7-column, 6-row grid. Players take turns dropping colored discs into any column, and the disc falls to the lowest available position. The first player to form a horizontal, vertical, or diagonal line of four discs wins. If all 42 spaces fill up without four in a row, the game is a draw.
On PlayVersusAI, you play as red against the AI (yellow). Choose from four difficulty levels, from beginner-friendly Easy mode to the punishing AI Training mode where the AI searches as deep as possible within a 2-second time limit.
Strategy Tips
- Control the center column -- Column 4 is involved in the most possible four-in-a-row combinations. Claiming it early gives you a strategic advantage.
- Build double threats -- Create positions where you can win in two places at once. Your opponent can only block one.
- Think ahead -- Don't just react to the AI's moves. Plan your own sequences and force the AI into defensive positions.
- Watch for diagonals -- Diagonal connections are harder to spot than horizontal or vertical ones. Keep an eye on both yours and the AI's diagonal threats.
- Use the odd-even strategy -- Threats on odd-numbered rows (from the bottom) are more valuable when it's your turn, because you control when they get filled.
Read the full Connect 4 guide →
Playing Connect 4 on PlayVersusAI
This is standard Connect 4 on the original 7-column, 6-row grid — 42 slots, gravity-fed, first to four in a line. You play red and move first, which matters more here than in most games: Connect 4 is mathematically solved, and the first player wins with perfect play. The opening move is yours to waste.
The engine behind the yellow discs stores the whole board in a pair of 64-bit integers and tests for wins with bitwise operations rather than scanning the grid. That sounds like trivia, but it is the reason the hardest setting can look a dozen moves ahead inside a two-second budget in a browser tab. It also means the AI never misses a win or an immediate block — anything you get past it has to be a threat it could not see the end of.
What's on This Page
- Four difficulty levels — switch between Easy, Medium, Hard and AI Training at any time, including mid-game.
- Built-in tutorial — an illustrated, step-by-step walkthrough of the rules on the board itself, via the How to Play button.
- Coach mode — live move analysis while you play, plus a full post-game review that marks where the game actually turned.
- Online multiplayer — play a friend in real time using a private room code, or take on a stranger from the public lobby.
- Tracked results — wins count toward your profile statistics and the site leaderboard.
- No account required — the full game is playable as a guest, on desktop, tablet or phone.
Easy is genuinely beatable and will let three-in-a-rows slide. Medium blocks reliably but rarely builds double threats of its own. Hard starts setting traps rather than just answering yours. AI Training is close to perfect play, and if you let it take the centre on move one you should not expect to win — the honest challenge at that level is taking centre yourself and holding the advantage.
Mistakes That Lose Games
- Playing entirely reactively. If every move you make is a block, you will eventually run out of safe squares and be forced to hand the AI a winning row. The engine is specifically good at engineering that position.
- Filling the square below the AI's threat. Dropping a disc into a column often hands your opponent the slot directly above it. Before every move, check what you are building underneath.
- Losing track of diagonals. Vertical and horizontal threats are easy to see. The AI wins most of its games on diagonals because people stop scanning for them once the board gets busy.
- Treating the edges as equivalent to the centre. Column one participates in far fewer winning lines than column four. Conceding the middle to save a tempo almost always backfires.
Connect 4 Questions
Can I beat the hardest difficulty?
Yes, but you need to move first and play accurately. Connect 4 is a solved game in which the first player wins by opening in the centre, so on AI Training the result usually comes down to who takes the middle column and whether you hold the odd-row threats afterwards. Going second against maximum difficulty is close to a lost cause, which is a property of the game rather than a quirk of our engine.
Why does the AI move instantly on Easy but pause on AI Training?
Because on the hardest setting it really is calculating. Easy stops after a shallow search; AI Training keeps deepening its search until its time budget runs out. The pause is the search, not an artificial delay.
Does Coach mode tell me the best move?
It tells you how good your intended move is and flags when you are about to throw away a winning position. After the game, the review walks through each move and marks the point where the evaluation actually swung — which is usually several moves before the game looked lost.
For the complete rules, the deeper strategy and the history of the game, read the full Connect 4 guide, or browse guides for all 20 games.