How to Play Knights & Knaves

Overview

Knights & Knaves puzzles are classic logic puzzles popularized by Raymond Smullyan. On a fictional island, Knights always tell the truth and Knaves always lie. Analyze their statements to deduce each character's type.

Video Tutorial

Rules

  • 1Each character is either a Knight or a Knave.
  • 2Knights ALWAYS tell the truth.
  • 3Knaves ALWAYS lie.
  • 4Use logic to deduce each character's type from their statements.

Character Types

Knight
Always tells the truth
🗡
Knave
Always lies

Example

A says: "B is a Knave."
B says: "We are both Knights."
Show Solution

A is a Knight, B is a Knave

If B were a Knight, "We are both Knights" would be true. But then A's statement would be false, making A a Knave - contradiction! So B is a Knave, and A correctly identifies this.

Solving Strategies

Assume and Test

Pick a character, assume they're a Knight, and check for consistency.

Look for Contradictions

If an assumption leads to contradiction, the opposite must be true.

Self-Reference Rule

Nobody can say "I am a Knave" - it's impossible for both types!

"Same Type" Statements

If X says "We are the same type," it's true if they are, false if they aren't.