How to Win Connect Four: Four in a Row Strategy

To win Connect Four, start in the middle column, ask what your disc lets your opponent do on top before you drop it, and build two threats at once so one of them can't be blocked. Late in the game, one more idea decides close games: the player who went first wants their threats on odd rows (1, 3, 5), and the player who went second wants them on even rows (2, 4, 6).

This guide explains each habit with a board you can check. Every position was verified with the game engine behind Poozee's Four in a Row, so you can set it up and play it out yourself. Rows are counted from the bottom and columns from the left. (Connect Four is a Hasbro trademark. Poozee's Four in a Row is our own version of the classic game, and we aren't affiliated with Hasbro.)

1. Start in the middle and keep coming back

The middle column is where most lines of four pass through. There are 69 possible lines of four on the board, and this table counts how many of them go through each spot:

A disc in column 4, row 3 is part of 13 different lines. A disc in a corner is part of 3. Every disc you put in the middle helps more future lines and blocks more of your opponent's.

It's also the right first move, and that isn't just an opinion: the game was solved in 1988. James Dow Allen and Victor Allis, working independently, showed that the first player wins with perfect play by starting in the middle column (John Tromp's summary has the history). Starting in column 3 or 5 lets the second player hold a draw, and starting in any of the four outer columns loses.

2. Ask three questions before every move

Most games between people are decided by a missed win or a missed block, not by deep strategy. Before every drop, ask:

1. Can I win right now? Check all seven columns, including the diagonals.
2. Does my opponent win next turn if I don't block? If yes, block, unless you can win first.
3. What does the spot above my disc do? Your disc turns the spot on top of it into a legal move. If that spot wins for your opponent, you just handed them the game.

The third question is the one most players skip, so it gets its own example.

3. Look under before you drop

Column 4 looks great for red. A red disc there makes three in a row on the bottom (columns 4, 5 and 6) with column 7 still open. But it lands directly under the star. Yellow drops in column 4 on top of it and wins across row 2.

Nothing forces anyone to play column 4 yet. If yellow drops there, red simply blocks row 2, and if red drops there, yellow wins. So the spot stays empty, and yellow's row 2 line waits for red to make a mistake. Red's safe choices here are narrow: Poozee's Hard computer, searching about 20 moves ahead, finds a forced win for yellow after every red move except columns 1 and 5.

Pro tip: When you spot a waiting threat like this, for either side, remember the column. As the board fills up, it's the column nobody wants to touch, and that is what the last section of this guide is about.

4. Make two threats with one move

Your opponent can only block one spot per turn. If one move creates two different winning spots, you win. The simplest version is an open three on the bottom row:

Red had discs in columns 2 and 3, and yellow had spent two moves in column 7. Red's drop in column 4 makes three in a row with both ends open and playable. Yellow blocks one end, red plays the other. We checked every yellow reply with the game engine and none of them stops red.

This only works on the bottom row, or higher up when the spots under both ends are already filled. So early in the game, if your opponent has two side by side on the bottom with empty space on both sides, block one side before it becomes three. The same idea works with diagonals and with two threats stacked in one column, and those are much harder for people to see coming.

5. Odd and even threats: how close games are decided

Between strong players, most threats can't be played right away. A threat here means an empty spot that would complete your four, with an empty spot under it. Neither player wants to fill the spot underneath, just like column 4 in section 3. So the columns with threats in them stay open while the rest of the board fills up, and eventually someone runs out of other moves and has to play under a threat.

Who runs out first comes down to counting. Victor Allis explains it in his 1988 thesis on Connect Four (sections 3.3 and 6.1): if the other columns fill up, the first player ends up with the odd squares in the last column and the second player with the even squares. That gives two rules:

• If you went first, aim for threats on odd rows (1, 3, 5). If you went second, aim for even rows (2, 4, 6).
• Two threats in the same column: the lower one usually decides the game, and a threat sitting directly on top of your opponent's threat is useless.

Here is an odd threat winning a game with no immediate threats on the board.

Red's threat is the star in column 2, row 3: red already has row 3 in columns 3, 4 and 5. Columns 1 and 2 are empty. Red plays like this:

1. Red drops in column 2. The disc lands on row 1, and now yellow can never play column 2, because a yellow disc on row 2 lets red land on row 3 and win.
2. Yellow has to play column 1, and red answers on top every time. Column 1 has six spots, so yellow fills rows 1, 3 and 5, and red fills rows 2, 4 and 6.
3. Column 1 is full and yellow must play column 2. The disc lands on row 2, and red wins on row 3.

We played out every yellow choice with the engine, and red wins in all of them. Even if it were yellow's turn in this position, yellow would still lose: the engine's exact search agrees. That's the power of a threat on the right row. Red didn't need a double threat. Red just needed yellow to run out of safe moves.

If you move second, the matching idea is to answer your opponent's move by playing on top of it in the same column. Allis calls this Claimeven: it hands you the even squares. Together with a handful of related rules, his thesis uses it to show the second player can always at least draw on a board like this one, as long as the first player didn't start in the middle column. It's a plan, not a reflex: always run the three questions from section 2 first.

Practice against the computer

The fastest way to get better is to play a lot of games and look back at the losses. On Poozee's Four in a Row:

• Easy sometimes misses wins and blocks, so it's good for practicing double threats.
• Medium never misses a one-move win or block, so you'll need threats it can't see a few moves ahead.
• Hard searches many moves deep and punishes a careless drop, like the one in section 3.
• Hint shows the column the Hard computer would pick for you, and who goes first switches every game, so you practice both sides.

If you like games where one careful look ahead beats fast play, try chess openings for beginners or the logic puzzles in Minesweeper patterns.

Keep playing

• Play Four in a Row against the computer or a friend
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• How to win tic-tac-toe, where the same double-threat idea decides every game
• Dots and boxes strategy: chains, control and the long chain rule
• Chess openings for beginners
• Sudoku strategies
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