Play twenty questions with someone

Twenty yes-or-no questions can in principle distinguish over a million possibilities, provided each question eliminates half of what remains. Almost nobody plays it that way. To play twenty questions with someone well is to resist guessing specifics early and ask the boring halving questions instead.

Why play twenty questions with someone is worth an hour

Each answer carries the most information when the answer was genuinely uncertain beforehand. A question with a ninety percent likely answer tells you almost nothing; a fifty-fifty question halves the field. Asking whether something is alive, or man-made, or larger than a car eliminates enormous categories in a way that guessing a specific animal never does.

How to play twenty questions with someone step by step

1. 1

   Establish the broadest category first

   Alive, man-made, abstract. One question eliminating a third of everything is worth ten specific guesses.

2. 2

   Aim for fifty-fifty questions

   A question you can genuinely not predict the answer to. Predictable answers carry almost no information.

3. 3

   Narrow by size and location next

   Bigger than a car, found indoors, would fit in a hand. Physical properties split categories cleanly.

4. 4

   Resist guessing until question fifteen

   Early specific guesses are almost always wrong, and each one costs you an entire question for no information at all.

5. 5

   Track the answers out loud

   Restating what you have already established prevents asking something answered three questions ago, which is the commonest waste.

Tips to get more out of it

• Agree upfront whether abstract concepts and fictional things are allowed. It changes the strategy considerably.
• With children, allow more than twenty questions and celebrate the good category questions rather than only the eventual win.
• The answerer should commit to their answer honestly from the start. Changing it partway through ruins the entire game.

Ways to mix it up

If you want it harder, reduce it to fifteen questions, which forces genuinely efficient questioning. If you are playing with a group, let everyone ask in rotation, which surfaces the difference between strong and weak questions immediately.

Play twenty questions with someone: frequently asked questions