Not yet — currently two-player only. Connect Four is mathematically solved (first player wins with perfect play); a hard AI would be unbeatable. Coming soon: easy / medium / hard AI modes with progressively more strategic depth.

What's the optimal opening move?

Center column (column 4 of 7). The center contributes to more potential winning lines than any other position — 4 horizontal, 1 vertical, 2 main diagonals, multiple sub-diagonals. Allis's 1988 proof showed that with center-first opening and perfect play, first player wins in 41 moves or fewer.

Who solved Connect Four?

James Allen (UK) and Victor Allis (Netherlands) independently in 1988. Allis's masters thesis ('A Knowledge-Based Approach of Connect-Four', Vrije Universiteit, 1988) is the canonical reference — it documents nine 'rules' that, when followed correctly, guarantee a first-player win. The proof was computer-assisted; the search space (~4.5 trillion possible positions) was too large for human hand-verification.

Why don't I just memorize Allis's strategy?

Because Allis's solution is technically a 41-move sequence with branches at every opponent reply — far too complex to memorize fully. What you can take away: (1) play center first; (2) prefer moves that create double-threats (two ways to win simultaneously); (3) avoid moves that give opponent a stack of pieces that becomes a winning threat. Most casual players don't know point 1, so applying it gives you a meaningful edge.

Are there variant rules?

Yes — Pop-Out (a piece at the bottom of a column can be removed, dropping the column down by one), Pop-Ten (first to score 10 points by making 4-in-a-row, with multiple per game), 5-in-a-row on a larger board (closer to gomoku). The version here is classic 7×6 first-to-4.

What's the world record?

Connect Four World Championships happen periodically (the most recent organized series was 2018-2020). Top players use openings drawn from Allis's analysis but with practical heuristics for time-pressured play. Best human players approach perfect play within a few moves' tolerance — a sub-1-minute speed game is essentially a memorization-vs-tactics duel.

Games · Free tool

Connect Four

Play Connect Four online on the standard 7x6 board. Two-player; drop pieces to get four in a row.

Updated June 2026

Red to move

Red wins

Yellow wins

Two-player. Click any column — your piece falls to the lowest empty row. Get four in a row (horizontal, vertical, or diagonal) to win.

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What it does

Two-player Connect Four on the standard 7-column × 6-row board. Players alternate dropping pieces into columns; gravity pulls each piece to the lowest empty cell in that column. First to align four pieces in a row — horizontally, vertically, or diagonally — wins. If the board fills with no winner, the game is a draw.

Connect Four was published by Milton Bradley in 1974, designed by Howard Wexler and Ned Strongin. The 7×6 board size and drop-piece-by-column mechanic were specifically chosen to be more strategically rich than tic-tac-toe but quicker than checkers. Cultural moment: the early-1980s Bill Cosby commercials made it one of the most-recognized board games of that era.

Mathematically, Connect Four is a solved game: James Allen and Victor Allis independently proved in 1988 that the first player wins with perfect play by playing the center column first. From that opening, careful play forces a win in 41 moves or fewer. With imperfect play (most human games), outcomes vary widely — beginners often lose to skilled second-players because they don’t know the center-column theorem; experts beat each other based on tactical fork-creation rather than positional theory.

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How to use it

Red goes first by convention. Click any column to drop your piece — gravity takes it to the lowest empty cell.
Yellow plays next. Repeat — same column-click mechanic.
First to align four pieces (horizontal, vertical, or diagonal) wins. The winning line highlights when achieved.
If the board fills with no winner, the game is a draw — rare but possible if both players play conservatively.
Strategy tip: the center column is the most valuable opening move. It contributes to more potential winning lines than any other column. Take it on move 1 if you're playing first.

When to use this tool

Casual two-player game with a friend, partner, or kid sharing a screen.
Demonstrating game-tree theory in CS or math education.
Quick break — typical games last 5-15 minutes.
Family game night — Connect Four is accessible to ages 6+ and adults.

When not to use it

Single-player practice — no AI in this version yet (a hard AI would be unbeatable since Connect Four is solved). Future versions will add easy/medium AI modes.
Tournament play — for serious Connect Four (yes, it's a competitive thing — Connect Four World Championship exists), use a dedicated platform with timer support and ELO tracking.
Multiplayer over the network — local-only.

Common use cases

Pre-decision sanity-check on inputs and outputs
Educational use — demonstrating the underlying concept
Onboarding a colleague who needs the same calculation/conversion
Verifying a number or output before passing it on

Frequently asked questions

Is there an AI?: Not yet — currently two-player only. Connect Four is mathematically solved (first player wins with perfect play); a hard AI would be unbeatable. Coming soon: easy / medium / hard AI modes with progressively more strategic depth.
What's the optimal opening move?: Center column (column 4 of 7). The center contributes to more potential winning lines than any other position — 4 horizontal, 1 vertical, 2 main diagonals, multiple sub-diagonals. Allis's 1988 proof showed that with center-first opening and perfect play, first player wins in 41 moves or fewer.
Who solved Connect Four?: James Allen (UK) and Victor Allis (Netherlands) independently in 1988. Allis's masters thesis ('A Knowledge-Based Approach of Connect-Four', Vrije Universiteit, 1988) is the canonical reference — it documents nine 'rules' that, when followed correctly, guarantee a first-player win. The proof was computer-assisted; the search space (~4.5 trillion possible positions) was too large for human hand-verification.
Why don't I just memorize Allis's strategy?: Because Allis's solution is technically a 41-move sequence with branches at every opponent reply — far too complex to memorize fully. What you can take away: (1) play center first; (2) prefer moves that create double-threats (two ways to win simultaneously); (3) avoid moves that give opponent a stack of pieces that becomes a winning threat. Most casual players don't know point 1, so applying it gives you a meaningful edge.
Are there variant rules?: Yes — Pop-Out (a piece at the bottom of a column can be removed, dropping the column down by one), Pop-Ten (first to score 10 points by making 4-in-a-row, with multiple per game), 5-in-a-row on a larger board (closer to gomoku). The version here is classic 7×6 first-to-4.
What's the world record?: Connect Four World Championships happen periodically (the most recent organized series was 2018-2020). Top players use openings drawn from Allis's analysis but with practical heuristics for time-pressured play. Best human players approach perfect play within a few moves' tolerance — a sub-1-minute speed game is essentially a memorization-vs-tactics duel.

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