How to play
Shut the Box is the old pub dice game: a wooden box with nine numbered tiles and two dice. On your turn you roll, then shut any set of open tiles that adds up exactly to the roll. A 7 can close the 7 alone, 1 and 6, 2 and 5, 3 and 4, or 1, 2 and 4. Tap the tiles you want; as soon as the selection reaches the total, the tiles flip down and you roll again. You cannot pass while a legal set exists, and tiles that can no longer complete a set are greyed out so every selection ends in a legal move.
Once the 7, 8 and 9 are shut (more precisely, once every open tile is 6 or lower) you may roll a single die instead of two. You can switch this rule off in the menu.
The turn ends when no open set matches the roll. Your score for the turn is the sum of the tiles still open; lower is better. Close every tile and you have “shut the box”: that scores 0 and wins the game on the spot, whatever the mode.
Modes:
- Solo, 1 / 3 / 5 rounds. Play the rounds and keep your total as low as you can. Only shutting the box counts as a win; otherwise the final total is your score.
- Solo, shut the box. Keep playing round after round until you shut the box. The game counts your attempts.
- Computer or friend, 1 / 3 / 5 rounds. You alternate rounds on the same screen. Lowest total after the last round wins; equal totals are a draw.
- Computer or friend, golf to 45. Rounds continue until someone’s total reaches 45. That player loses.
Options also include a 12-tile box. The game saves after every move and resumes where you left off; “Give up” in the menu ends the current game.
Strategy
With nine tiles there are only 512 possible positions, so the best play can be worked out exactly, and that is what the computer opponent and the Hint button use. A few patterns from that calculation:
- Keep the small tiles. Low tiles combine into almost any total; a box with 1, 2 and 3 open can still absorb most rolls, while a box with only 8 and 9 open needs exactly 8, 9 or 17. When a roll of 7 gives you the choice, closing the 7 is usually better than 3 and 4, and 3 and 4 is usually better than 1, 2 and 4.
- Use the single die. Once only tiles 1 to 6 remain, one die gives a 1-in-6 chance at each remaining tile and can never roll a total that is impossible to make. With one tile left, two dice cannot shut a 1 at all.
- Know the odds. Playing for the lowest possible score, the exact expected result of a round is 11.0 points on the nine-tile box. Playing purely to shut the box, the chance of closing all nine is 9.8% with the single-die option and 7.1% when two dice are compulsory. In 20,000 simulated rounds the score-minimising strategy averaged 11.0 points and shut the box 9.3% of the time.
- Twelve tiles is a different game. The expected score climbs to about 35 and the box shuts in roughly 1 round in 200, because 10, 11 and 12 can only be closed by combinations.
- Against an opponent the computer simply minimises its expected score every round. If you are far behind on the last round you may prefer riskier closes that keep the chance of a 0; the Hint button will not suggest that, so treat it as a baseline, not a rule.
If you enjoy Shut the Box, try Snakes and Ladders or Tablut next.
