How do you play Four on the Hill?
Four on the Hill is a two-player game of gravity and lines on a board of 9 columns. The columns are 3, 4, 5, 6, 7, 6, 5, 4, 3 cells tall, so the board rises to a peak in the middle and holds 43 discs.
- Drop. Pick a column and your disc falls to its lowest empty cell.
- Follow. After the first move, play in the column your opponent just used or one right beside it. If all of those are full, play any column with room.
- Win. Four of your discs in a straight line across, up or on a diagonal wins. Lines only count cells that exist on the hill.
- Draw. If all 43 cells fill up with no line of four, nobody wins.
What does the follow rule look like in a real opening?
The follow rule turns every move into a choice about where your opponent will have to play next. Here is the start of one game:
- Blue opens in column 5, the middle. The first move may go anywhere.
- Amber must answer in column 4, 5 or 6 and picks column 6.
- Blue now has to play column 5, 6 or 7, the three columns marked below. Column 9 is out of reach this turn, however open it looks.
Which cells and columns are worth the most?
The hill has exactly 66 possible lines of four: 24 across, 16 going up and 26 on the two diagonals. A cell is worth more when more of those lines pass through it.
| Column | Cells | Lines that use it |
|---|---|---|
| 1 | 3 | 6 |
| 2 | 4 | 16 |
| 3 | 5 | 27 |
| 4 | 6 | 38 |
| 5 | 7 | 42 |
| 6 | 6 | 38 |
| 7 | 5 | 27 |
| 8 | 4 | 16 |
| 9 | 3 | 6 |
Counted by the game's own code from the board shape. A line counts once for a column if any of its four cells is in that column.
What strategy works on the hill?
- Take the peak early. The middle column touches 42 of the 66 lines and its 4th cell sits on 12. The edge columns touch only 6 each.
- Use the edges to box your opponent in. A disc in column 1 or 9 leaves your opponent only 2 columns to answer in, so you can often predict their reply.
- Check whether a threat can be reached. A winning gap two or more columns away from the column you play is out of your opponent's reach next turn, because they must play within one column of you. Before blocking, look at where they are allowed to go.
- Watch for full neighbours. Filling the last cell of a column whose neighbours are already full frees your opponent to play any column. Avoid that move unless you want them loose.
Questions
What is the follow rule in Four on the Hill?
After the first disc, each player must drop into the column the other player just used or a column right next to it. So after a disc in column 5, the reply goes in column 4, 5 or 6.
What happens if the columns I must follow are full?
Then you are free. When the last column and both of its neighbours have no room left, you may drop into any column that still has an empty cell.
How do the computer levels differ?
Easy looks two moves ahead and plays a random column three times in ten. Medium looks four moves ahead, always takes a win, and stops yours whenever a legal move can. Hard keeps looking deeper until it has used 800 milliseconds, and it thinks in the background so the page stays smooth.
Can a game end in a draw?
Yes. The hill has 43 cells, so the game stops when the 43rd disc lands without anyone making four in a line. An odd cell count means the player who starts drops one disc more.
Where is my record kept?
Wins, losses and draws against each level stay in this browser. Nothing is sent anywhere, and the link under the board wipes them.