Knights & Knaves

Who always lies and who always tells the truth?

10 RiddlesKnights & Knaves

Two Doors

You stand before two doors. One leads to freedom, one to doom. Two guards stand watch — one always tells the truth (knight), one always lies (knave). You don't know which is which. You can ask ONE guard ONE question. What do you ask?

Solve →

hardAdults (18+)Interactive

A, B, and C

Three people A, B, C are either knights (always true) or knaves (always lie). A says: 'We are all knaves.' B says: 'Exactly one of us is a knight.' What are A, B, and C?

Play →

mediumTeens (13-17)

What Am I?

A person says: 'I am a knave.' Is this person a knight or knave?

Solve →

mediumAdults (18+)

Three Guards

Three guards stand at a gate. Guard 1: 'Guard 2 is a knight.' Guard 2: 'Guard 1 is a knave.' Guard 3: 'Guard 2 is a knave.' How many guards are knights?

Solve →

easyTeens (13-17)

Island Logic

On an island, every person is a knight or knave. You meet two islanders. Person A says: 'We are both knights.' Person B says nothing. What can you conclude?

Solve →

mediumAll Ages

Which Path?

A traveler at a fork meets a local who is either a knight or knave. The traveler asks 'Is the left path safe?' The local says 'Yes.' Can the traveler trust this?

Solve →

easyTeens (13-17)

The Sole Knight

In a group of 5 people, exactly one is a knight. They all say: 'I am the knight.' Which one is telling the truth?

Solve →

hardAdults (18+)

Are You Married?

Two people: Person X and Person Y. Person X: 'If I am a knight, then I am married.' Person Y: 'If I am a knight, then Person X is married.' Is Person X married?

Solve →

hardAdults (18+)

Am I Lying?

A person on the island of knights and knaves says: 'I am lying right now.' Is this person a knight or a knave?

Solve →

easyKids (5-12)Interactive

One Simple Question

You are on the island. A person says: 'Two plus two is five.' Is this person a knight or a knave?

Play →

← Browse All Categories