Four-eyed lineups

Play Connect Four in your browser! Win by aligning 4 pieces vertically, horizontally, or diagonally. Supports CPU and 2-player modes.

No download needed! No login required! Play directly in your browser!

🌐 Online Battle
Your turn (Red)
▲
Lv.1
0/50 XP

treatment

  • Click the arrow button above the column to drop the piece
  • The pieces fall down by gravity and are placed in the lowest available space
  • You win if four of the same color are lined up vertically, horizontally, or diagonally.
  • CPU is a powerful opponent as it anticipates with Minimax (depth 5)
  • Choose whether you want to play first (red) or second (yellow), then press "New Game"!

What is Connect Four?

Connect Four is a classic two-player strategy game where players drop colored pieces into a vertical grid, competing to align four of their pieces in a row—horizontally, vertically, or diagonally. The web version lets you play against the computer or a friend, making it accessible anywhere without a physical board. It's a perfect blend of simple rules and strategic depth.

How to Use

Click the column header where you want to drop your piece. Your piece falls to the lowest available position in that column. The opponent (CPU or human) plays next. Continue taking turns until someone aligns four pieces or the board fills completely in a draw. Against the CPU, the AI evaluates threats and opportunities, so focus on creating double threats—situations where two winning moves exist, forcing your opponent to block only one. The game resets after each round, and most versions show game history, letting you analyze your moves or play multiple matches.

Use Cases

• A parent and child play together on a tablet during a long car ride, taking turns as the human and CPU opponent to keep everyone entertained without needing a physical game.
• A student uses Connect Four strategy to develop logical thinking and planning skills, playing progressively harder difficulty levels to sharpen competitive reasoning.
• A team takes a quick break during a workday, challenging colleagues to rapid matches. The browser-based version requires no setup, installation, or physical space.
• A player practices offensive and defensive strategies against the CPU on different difficulty settings, learning how positioning early in the game determines endgame outcomes.

Tips & Insights

The center column is strategically valuable because pieces placed there create more potential alignment combinations than edge columns. Winning requires thinking multiple moves ahead and anticipating your opponent's threats. Experienced players often sacrifice immediate wins to set up unblockable multi-move threats. The AI difficulty levels vary: easy opponents make random moves, medium opponents block threats, and hard opponents play near-optimally. Understanding these patterns helps you identify which strategies work against different skill levels.

Frequently Asked Questions

What are the rules?

The first player to line up four pieces of the same color in a row, either vertically, horizontally or diagonally, wins. Click on a row to drop a piece.

How strong is the CPU?

It uses the Minimax algorithm (depth 5) and is quite powerful. It reads the jamming or anticipates the winning pattern.

What about draws?

If the entire board is filled and there is no winner, the game is a draw.

Can I choose the first or second move?

At the beginning of the game, you can choose whether to play first (red) or second (yellow).

What's the best opening move in Connect Four?

The center column is generally considered the strongest opening because it gives you more opportunities to create winning patterns in multiple directions. Starting in the middle-adjacent columns is also strong. Avoid edge columns as much as possible early in the game, as they offer fewer winning path options.

How can I block the opponent's winning move?

Always watch for situations where your opponent has three pieces in a row. Block immediately by placing a piece adjacent to their line before they complete it. Blocking is crucial in the middle and upper portions of the board where pieces accumulate. Sometimes you'll need to sacrifice good positioning to prevent an immediate loss.

Can the game end in a tie?

Yes! If the board fills up completely and no player has connected four pieces, the game is a draw. The 6x7 board (42 spaces total) can fill quickly with defensive play. This is more common in games between experienced players or when playing against the CPU on higher difficulty.

What's the 'trap' strategy in Connect Four?

A trap is when you create two ways to win on your next turn, forcing your opponent into a losing position since they can only block one. Build toward this by positioning three pieces strategically with an open space that threatens multiple directions. Spotting and preventing opponent traps is key to winning.

Does the first player always have an advantage?

Yes, the first player has a slight advantage in Connect Four. Going first lets you control the center columns and set the game's pace. However, this advantage is small enough that skilled play can overcome it. With perfect play, the game is usually drawn between two expert players.

Can I undo a move if I make a mistake?

This depends on the implementation. In most browser versions, you cannot undo moves during active gameplay. However, you can start a new game anytime. If you need to undo, consider using your browser's back button before refreshing, though this will reset the entire game state.