No.276
Single-Pile Take-Away Game
Japanese name: 石取りゲーム
Materials
- 21 large counting sticks or cards
- Paper to record the numbers
How to play
- Place 21 sticks in the middle and choose who goes first. On each turn, take 1–3 sticks. Make clear that the person taking the last stick loses.
- Alternate turns, saying how many sticks were taken and how many remain. Even when three or fewer remain, the player must take at least one.
- Taking the last stick ends the round. Reset to 21 sticks, swap who goes first and play again.
- After two rounds, discuss which numbers of remaining sticks were difficult. To continue, change either the starting number or the maximum taken per turn, but not both at once.
Ways to adapt
Primary children: start with 11 sticks and take 1–2 per turn. Show the taking limits and losing condition with a diagram.