What this game is
Mancala is not one game but a whole family, the oldest of anything played on this site. The board is a row of holes in the ground, and the pieces are pebbles or seeds.
The version here is Kalah: six pits a side, four seeds in each and a store at either end. A move looks disarmingly simple — pick up a handful, drop them one at a time anticlockwise — but the whole game grows out of that.
It comes down to two rules. Land your last seed in your own store and you move again, and such chains can run five or six turns long. Land it in an empty pit of yours and you capture everything facing it, sometimes a dozen seeds at once. Games are decided by whoever counts those two things further ahead.
Rules
- Your six pits are the bottom row and your store is on the right. The computer owns the top row and the store on the left. You move first.
- A move is a click on one of your non-empty pits. Every seed in it is picked up and dropped one per pit going anticlockwise: right along the bottom row, then your store, then left along the top row.
- Your own store gets a seed on the way past. The opponent's store never does — it is skipped.
- If the last seed lands exactly in your store, you move again, as many times in a row as you can manage it.
- If the last seed lands in an empty pit on your side and the pit facing it holds seeds, you capture those seeds together with your last one and put them all in your store.
- As soon as one player's six pits are all empty the game ends, and the other player moves whatever is still in front of him into his own store.
- The bigger store wins. There are 48 seeds in all, so 25 is enough. An exact 24–24 is a draw, and a draw is added to neither tally in the strip below.
How to play better
- Look first for a move that ends in your store: it is a free extra turn. From the opening position exactly one move does that — the third pit from the left: four steps from the store, with four seeds in it.
- Chains beat single moves. It is often worth playing a weak-looking move if it sets up two or three extra turns in a row after it.
- Keep an empty pit as a trap. If you can drop your last seed into it once a handful has piled up opposite, that is ten seeds in one move.
- The reverse holds too: watch the opponent's empty pits and how much you have sitting opposite them. Do not fill a pit that is about to be swept.
- Hoarding seeds in the pits nearest your store is convenient and risky: one move scatters a big handful across the whole board, the opponent's half included.
- Near the end, count literally. With few seeds left the game can be read to the finish in your head, and arithmetic beats instinct.
A bit of history
Mancala is probably the oldest game mechanic still in use. Rows of carved holes turn up all over Africa and the Middle East, the oldest of them thousands of years old, and the game is still played today under hundreds of names: awari, oware, bao, congkak.
Kalah is the twentieth-century American version: its rules were fixed and patented by William Julius Champion Jr., and it is this variant that ended up in school board-game sets.
Mancala turned out to be a good target for computers. Kalah with six pits and four seeds was solved in 2000: with perfect play the first player wins. Awari, the stricter African variant, fell in 2002 to John Romein and Henri Bal, who enumerated all 889 billion positions and proved the game a draw. Awari is listed in our reference of solved games.
About the levels
Easy looks exactly one move ahead. It takes whatever pays most right now: an extra turn first, then a capture, then plain seeds banked. What the position looks like afterwards it never checks — so it keeps filling the pit you are about to sweep.
Hard builds an eight-move tree with alpha-beta cut-offs. The tree has a quirk in Kalah: a move ending in your own store does not pass the turn, so that branch continues with the same player and costs no depth — chains of extra turns are searched whole, however long they run.
Expert is the same search with time-limited deepening: six moves, then seven, and so on for about a third of a second. It scores mostly by the difference between the stores, with small bonuses for seeds still on its own side and for pits that would earn an extra turn. Late in the game, with few seeds left, it reads the position to the very end and stops making mistakes.