Last updated: March 2026
What Is Connect Four?
Connect Four is a free online two-player strategy game where you drop colored discs into a vertical grid, aiming to connect four in a row horizontally, vertically, or diagonally. No signup, no download required. Take turns dropping red and yellow discs into a 7-column, 6-row board. The first player to line up four consecutive discs wins.
Created by Howard Wexler and patented by Milton Bradley in 1974, Connect Four has sold over 50 million copies worldwide and is mathematically solved. Victor Allis proved in 1988 that the first player can always force a win with perfect play starting from the center column. Despite being solved, the game remains deeply engaging because humans rarely play perfectly, making every match unpredictable.
This version features 3 AI difficulty levels ranging from random moves to minimax with alpha-beta pruning, disc drop animations, undo, and score tracking. Play against the computer or pass-and-play with a friend on the same device.
How to Use Connect Four
Choose your mode at the top: vs AI (with Easy, Medium, or Hard difficulty) or vs Friend for same-device two-player games. The AI ranges from making random moves on Easy to searching six moves ahead with alpha-beta pruning on Hard.
Click or tap any column to drop your disc. It falls to the lowest available slot with a smooth drop animation. A ghost disc previews where your piece will land when you hover over a column.
Connect four discs in a row horizontally, vertically, or diagonally to win. Winning discs pulse with a glow effect. If all 42 cells fill without a winner, the game is a draw.
Use the Undo button to take back a move (vs AI, it undoes both your move and the AI response). The score tracker keeps a running tally across games. Hit New Game to reset the board while preserving your record.
Key Features
The three AI difficulty levels cover every skill level. Easy mode makes mostly random moves with occasional blocking, perfect for casual play. Medium searches three moves ahead and plays a solid game. Hard uses minimax with alpha-beta pruning at depth six, evaluating tens of thousands of positions per turn to find strong moves.
Every disc drop features a smooth fall animation with a slight bounce at the bottom for satisfying game feel. The classic blue board with red and yellow discs matches the look of the physical game. Winning discs are highlighted with a pulsing glow animation so the winning line is instantly visible.
The game works perfectly on desktop and mobile. The board resizes responsively with a minimum cell size of 44px for easy touch targets. No signup, no downloads, no ads. Load the page and play immediately.
Frequently Asked Questions
How do you win at Connect Four?
Control the center column — discs placed there participate in more potential four-in-a-row lines than any other position. Build threats in multiple directions simultaneously so your opponent can't block everything. Avoid playing on the edges early, as they limit your future options. Setting up a double threat (two ways to win at once) is the most reliable path to victory.
Can you always win Connect Four if you go first?
Mathematically yes — Connect Four was solved in 1988 by Victor Allis. The first player can force a win with perfect play by starting in the center column. In practice, this requires flawless play across dozens of moves. The Hard AI in this tool plays at a very strong level using minimax with alpha-beta pruning at depth 6, but it is not perfect.
What is the best opening move in Connect Four?
Always drop your first disc in the center column (column 4). It gives you the most winning possibilities because it participates in the highest number of potential four-in-a-row combinations — horizontal, vertical, and both diagonals. Starting anywhere else allows the second player to equalize with correct play.
Can two players play Connect Four on the same device?
Yes — select the "vs Friend" mode. Players alternate turns on the same screen. The board labels whose turn it is and tracks both players' scores across multiple games. Player 1 is always Red and goes first; Player 2 is Yellow.
How strong is the Hard AI?
The Hard AI uses minimax with alpha-beta pruning searching 6 moves ahead, evaluating tens of thousands of positions per move. It blocks your wins, exploits double threats, and prioritizes the center column. It is beatable with strategic thinking, but you will need to plan several moves ahead and set up threats it cannot fully counter.