Kalah is a modern variation in the ancient Mancala family of games.

The Kalah board was first patented and sold in the United States by William Julius Champion, Jr. in the 1950s.

The last seed falls in the store, so the player receives an extra move.

The last seed falls in an empty house on the player's side.

Kalah was implemented on the PDP-1 in the early 1960s,[3] and was able to out-play experienced human players.

[4] Since then, there have been myriad Kalah implementations for various operating systems and platforms, including DOS,[5] and the Nokia 3310.

A clever player can take advantage of this rule to chain together many extra turns.

The longest possible such chain on a standard Kalah board of 6 pits lasts for 17 moves.

On a general n-pit board, the patterns of seeds which can be cleared in a single turn in this way have been the object of mathematical study.

These patterns require arbitrarily long rows of pits and n increases.

Let s(n) denote the minimum number of seeds which requires n pits to clear.