Rules for "20 Questions" (The Yes/No Guessing Game)

The game you describe—one person thinks of something, others ask yes/no questions to guess it in ≤20 questions—is the classic 20 Questions.

📜 Standard Rules

1. Thinker secretly chooses a Person, Place, Thing, or Concept (concrete nouns work best)
2. Questioners take turns asking Yes/No questions only
3. Thinker answers truthfully: "Yes," "No," "I don't know," "Sometimes," "Irrelevant"
4. Limit: 20 questions total (not per person)
5. Guessing: A questioner may use a turn to guess the answer directly ("Is it a car?"). If wrong, it counts as a question. If right, they win
6. Win: Questioners guess correctly within 20. Thinker wins if they don't

🎯 Strategic Question Flow (Binary Search)

1. Kingdom: "Is it a living thing?" → Animal / Vegetable / Mineral / Abstract
2. Category: "Is it man-made?" "Is it larger than a breadbox?"
3. Function: "Is it used for transportation?" "Entertainment?" "Work?"
4. Specifics: "Is it a vehicle?" → "Four wheels?" → "Car?" → "Sedan?"

🧩 Popular Variants

• Animal, Vegetable, Mineral: Thinker states category upfront
• Celebrity / Fictional Character: Only people/characters
• Electronic / App Versions: 20Q (handheld), Akinator (web/app) — AI guesses *you*
• Team Play: Teams confer on questions
• For Kids: Use picture cards; limit to 10 questions; allow "Hot/Cold" hints

💡 Pro Tips

• Broad → Narrow: Don't waste early questions on specifics
• Listen to Answers: "I don't know" is valuable info (thinker's uncertainty)
• Track Questions: Designate a counter
• No Leading: "Is it a red car?" assumes car. Ask "Is it a vehicle?" then "Is it red?"

Simple, zero-equipment, infinitely replayable. Perfect for car rides, waiting rooms, or campfires.