Shut the Box: Rules, Real Odds, and a Strategy That Actually Helps

Shut the Box is one of those games that takes thirty seconds to learn and a lifetime to stop losing at. You have nine tiles numbered 1 to 9, two dice, and one goal: flip every tile down. You can play Shut the Box online free on this site, and this guide covers the rules, the actual odds, and what helps.

The rules in one minute

Roll the dice. Flip down any open tiles that add up exactly to the roll: a 9 can be the 9 alone, or 5 + 4, or 6 + 2 + 1. Keep rolling until you shut every tile, or until you roll a number you cannot make from the tiles that are left. Your score is the total of the tiles still standing, so lower is better, and zero is a perfect game. In the version here, once the 7, 8 and 9 are all down you roll a single die, which is a common pub rule. The game is also called close the box, canoga, or batten down the hatches.

The real odds

I wanted a straight answer to how often a perfect game is even possible, so I calculated it exactly instead of guessing. The method is simple: check every possible board, all 512 combinations of open and shut tiles, and for each roll find the move that gives the best chance of finishing.

The result: with perfect play you shut the box in about 7.4% of games, roughly one in thirteen. Perfect play still averages a final score of about 11.7. Two common habits, always taking the single biggest tile you can or always using up small tiles first, both shut the box about 5.6% of the time. Good decisions are worth about a third more perfect games, but luck decides most of it, which is part of the charm.

Why the high tiles matter most

With two dice, 7 is the most likely roll (6 ways out of 36), then 6 and 8 (5 ways each), while 2 and 12 have just one way each. Small numbers are easy to make from combinations late in the game; big numbers are not. And once you are down to one die, anything above 6 can never be made. A board with the 8 or 9 still standing at that point is already lost.

Habits that help

Clear 7, 8 and 9 early while you still have two dice. When you can split a roll, prefer the split that keeps your options open: a mix of low and middle tiles gives you more ways to make future rolls than a cluster of high ones. Think about the switch to one die before it happens. If the next likely rolls cannot finish off a high tile, deal with it now.

Why it is good for kids

Every turn is a small mental-maths puzzle: which numbers add up to 9? Is it better as 6 + 3 or 5 + 4? Kids practise addition without it feeling like homework, and the luck element means a beginner can beat an adult, which keeps everyone at the table.

Ready to test the odds yourself? Play Shut the Box online. It is free, works on phones, and saves your best score.