Play Four in a Row Online vs AI
How to Play Four in a Row
Play Four in a Row online on a 7×6 gravity board: red drops first, players choose a column, and the first to connect four matching discs horizontally, vertically, or diagonally wins. Start against multiple AI levels on this page with hints, undo, and replay, or switch to same-device play or an online room for a game with a friend.
How Four in a Row Works
The board has seven columns and six rows. Each turn, a disc drops into one column and falls to the lowest open slot. Red always starts; blue follows. The first player to line up four discs of their color horizontally, vertically, or diagonally wins.
A full column cannot take another disc. If all forty-two slots are filled and nobody has four, the game is a draw. Discs never move once they land, so every column height is part of the next decision.
Columns Set the Height
After you tap a column, the disc always occupies the lowest empty slot. It cannot hover or skip over discs already there. You are rarely claiming a particular cell; you are deciding which height that column will offer next. The center column runs through the most four-in-a-line windows, so it is often contested early. But if a threat of four is already on the board, blocking that column comes first.
Make Two Threats
If your opponent can complete four on the next drop, you must block that column. If you can complete four yourself, take it. The hard case is a double threat: one disc leaves two independent winning columns, and the opponent can cover only one. When you review a loss, the last missed four is usually already too late; look back for the move that let both threats appear together.
AI Play
The home page opens in AI mode. You can play red or blue and switch among multiple strength levels. A hint marks a candidate column; undo returns to the previous position so you can try another column; the move list and replay show which drop created a double threat. Search runs in the browser.
7×6columns by rows
42slots on the board
4in a line to win
Redalways drops first
Common questions
What rules does this Four in a Row game use?
The standard ones. The board has seven columns and six rows, and red goes first. Players take turns dropping a disc into a column, and it falls to the lowest empty slot. Four of your color in a line, across, up or diagonally, wins. If all 42 slots fill with no line of four, the game is a draw.
Does going first really give you an edge?
Yes, a real one. The game was solved by computer decades ago: if red opens in the middle column and never slips, red always wins. That's theory, though. People miss things over the board, so blue still wins plenty of games. When playing a friend for keeps, play in pairs and swap who takes red.
Why does everyone go for the middle column?
The middle column sits in more possible lines of four than any other, and most horizontal and diagonal lines run through it. A disc on the edge has far fewer ways to become part of a four. Leaning toward the center early is usually right, but don't cling to it. If your opponent has three in a row, blocking comes first.
I kept blocking, so why did I still lose?
You were probably caught by a double threat. One drop left your opponent with two different spots that would each make four, and you could only cover one. By the time it's visible, it's too late. In the replay, skip past the final move and step back to where your opponent first had two threes going. That's usually where it slipped.
Why would I avoid a column that's still open?
Because discs stack. Drop into that column and you hand your opponent the slot right above. If that slot finishes their four, you've just set it up for them. Before every drop, look one row up and ask who that square helps more.
Which AI level should I pick?
If you're new, start on the easiest one. It makes mistakes, which gives you room to build a double threat and see how wins actually happen. Once you're beating it reliably, move up a step. The top level hardly ever misses, so beating it as blue is tough, but it's a good way to find out what you've been overlooking.
When should I use hints, undo, and replay?
A hint marks one column, and it's always calculated at the strongest level, so treat it as an answer key. Pick your own column first, then check the hint and work out why they differ. Undo takes you back a move so you can try something else. Replay is best after the game ends, to find the move where things started to go wrong.
Do I need an account or an app?
No. There's no sign-up and nothing to install. Open the page on a phone or computer and start dropping discs. The AI runs entirely in your own browser. If you'd like one-tap access later, you can add the site to your home screen, but you don't need to.
If I close the page, is my game still there?
Usually, yes. Games against the AI are saved in this browser on this device, with one game kept for red and one for blue. Two-player games on one screen are saved separately. A different phone or computer won't have them, and clearing your browser data removes them too.
How can I play with a friend?
If you're in the same room, open the two-player mode and pass one device back and forth. No internet needed. If you're apart, create a room in online play. Send a private room's link straight to your friend, or open a public room and wait in the lobby. Online games have no hints and no one-sided undo.
