Why the last Mancala seed decides the turn

Published

This is one subject: you pick up a bowl, and the bowl where the last seed lands decides whether you play again, capture, or simply stop. This edition is Kalah with six bowls a side and four seeds in each. There is no pie-rule swap of sides after the first move.

1. Sow counterclockwise and skip their store

Choose a bowl on your side that has seeds. Lift all of them and drop one into each next bowl, moving counterclockwise. Your own store receives a seed when the sow passes it. The opponent’s store is skipped. You cannot start from the opponent’s bowls or from a store.

2. The last seed is an extra turn or a capture

If the last seed lands in your store, you play again. If it lands in an empty bowl on your side, and the opposite bowl has seeds, you capture: the last seed and the opposite seeds go into your store. If that opposite bowl is empty, nothing is captured. Landing in the opponent’s bowls does not capture.

3. An empty side ends the sowing

When every bowl on one side is empty, the seeds still sitting on the other side go into that other side’s store, their owner’s store. The larger store wins. Equal stores draw. South sows first in a new game on this page.

Examples on this board

  1. One seed next to your store. The bowl immediately before your store holds one seed and you choose it. That seed drops into your store. You take another turn. Choosing a heavier bowl farther away would have walked past the store and ended in a different bowl.
  2. A capture. An empty bowl on your side sits opposite a bowl with three seeds. You sow so the last seed falls into that empty bowl. Your store receives that last seed plus the three from across the board. The opposite bowl is left empty.
  3. The opposite bowl is empty. The last seed still lands in an empty bowl of yours, but the bowl across from it has no seeds. You do not capture. The last seed stays where it landed, and the turn passes.
  4. Their store is not a hole you fill. A long sow reaches the far end, passes your store, and continues up the opponent’s side. It does not drop a seed into the opponent’s store. The count of steps skips that store, so the landing bowl is one farther on than a player who counts every pit will expect.
  5. The ending sweep, and a quiet queue. Your six bowls are empty and North still has seeds. Those remaining seeds go into North’s store, not into yours, and the stores are compared. If you had been in the public queue instead of playing, about ten seconds with no other person starts a computer game. The computer uses this same Kalah, with no pie rule.

Why it matters

The biggest bowl is the obvious grab, and it is often the wrong one. A single seed that ends in your store is another whole turn. A last seed that ends opposite a full bowl is a capture. A last seed that ends anywhere else is just a moved pile. Counting only the size of the bowl hides which of those three endings you are choosing.

The date is the day this was checked against the live Kalah board: six and four, no pie rule, and the about-ten-second computer game when the random queue is empty.

Closing

Count the landing of the last seed before you pick the bowl up. Take the extra turn when it is there, capture only when the opposite bowl is occupied, and expect the other side’s leftover seeds to stay with their owner at the end. An empty queue becomes the computer after about ten seconds. The about page says what the site is. The privacy page says what it stores.