Connect Four

Overview

Two players drop coloured discs into a standing seven-column, six-row grid. The first to line up four of their own discs wins.

This entry is checked against Hasbro's Connect 4 rules for the edition with the PopOut bar (©2008), which include the Original game and two variants.

1. Setup

Stand the grid upright between both players. One takes all 21 yellow counters, the other all 21 red. The rules simply say "Decide who's going first". There is no rule that yellow, or red, starts.

2. Play

1. On your turn, drop one disc into any column that is not already full.
2. The disc falls to the lowest empty slot in that column. You choose the column, never the height.
3. Play alternates until someone wins or the grid fills.

You may not remove or reposition a disc once dropped, and you may not pass.

3. Winning

Four of your discs in an unbroken straight line, in any of three orientations:

• Horizontal — four along a row
• Vertical — four stacked in a column
• Diagonal — four along either diagonal

Diagonal wins count. They are the most commonly missed threat, precisely because players scan rows and columns first.

A square does not win

Four discs forming a 2×2 square is not a win. Neither is any other shape — an L, a T, a cross, or four in a scattered cluster.

The line must be straight and unbroken. This is the single most common misunderstanding of the game, and it comes up constantly with children, who reasonably assume four touching discs should count.

4. Can the game be tied?

Yes. Hasbro's sheet doesn't mention it, but if all 42 counters are in and nobody has four in a row, nobody has won. The rules give no tie-breaker, so it's a draw.

Championship play: each player has a scoring slide. Move it up one per game won; first to five is the Connect 4 champion.

5. Strategy

Connect Four is solved. With perfect play from both sides:

• The first player wins by opening in the centre column.
• Opening on an outer column loses.
• The two columns either side of centre draw.

The practical consequences for real games:

Take the centre. It participates in more possible lines than any other column.

Count parity. Threats on odd-numbered rows favour the first player; even rows favour the second. Strong play often comes down to forcing your opponent to fill the slot beneath your winning square.

Watch for double threats. Creating two winning squares at once is unanswerable, and is how most games are actually won.

6. Variants

Two variants are in the official rules for grids with a PopOut bar:

• PopOut — on your turn you may either drop a counter in or pop one of your own out of the bottom row, dropping everything above it down a slot. You can only drop or pop your own colour.
• Pop 10 — start with a full grid. Take turns popping out one of your own counters from the bottom row. If it was part of a four-in-a-row, keep it and pop again; if not, put it back in at the top, in a different column unless there's no other choice. First to collect 10 counters wins.

Other versions, such as Connect 4x4 and Connect 4 Spin, are separate products with their own rules.

Commonly argued

• A square is not a win. Straight lines only.
• Diagonals absolutely count, in both directions.
• A full grid with no line is a draw. There is no tie-breaker.
• Neither colour has to go first. Decide between you.
• In PopOut you can only pop your own counters.
• You cannot choose the height a disc lands at, only the column.
• The first player wins with perfect play, but only by starting in the centre.