So the traditional answer here is to ask them to point at the door the other guard will say is safe.
However, I'm curious, does anyone know of any other valid solutions?
this post was submitted on 23 Oct 2025
689 points (97.3% liked)
RPGMemes
14083 readers
883 users here now
Humor, jokes, memes about TTRPGs
founded 2 years ago
MODERATORS
Could probably do something clever with XOR.
Is exactly one of the following statements true? You are the liar. Your door is the safe door.
load more comments
(15 replies)
This doesn't help the party decide which door to go through at all
The first time I encountered a version of this riddle it actually wasn't Labyrinth. It was an old black and white episode of Dr Who aired on PBS when I was a little kid. Same scenario but if I recall, robots instead of guardsmen. I think the good doctor solved the riddle in the typical way of asking one robot what the other would say. I'm looking for it now but I can't find the scene.
Pyramids of Mars
Yes, thank you!! Found the scene itself since the whole serial is apparently on youtube: https://youtu.be/lLBHbt9QYFU?t=5458
Funny how my memory had it in black and white. And I remember the scene being much longer. I watched it when I was like, 9.
Maybe your childhood TV was black and white.
Length, brains just love to add details that dont exist
This puzzle is always presented as difficult, but why not just ask a known? If your eyes are brown just ask “Are my eyes brown?” You’d immediately know which one lies or tells the truth.
E: I missed the limit of one question.
Because there are two doors and only one question. If you ask a known question unrelated to the door you find out who the liar is but lose your opportunity to ask them which is the correct door.
Knowing who lies and who tells the truth doesn't tell you which door leads to the prize and which to death.
The difficulty comes from only being able to ask one question. It's very easy to figure out the liar, but it's much more difficult to figure out the liar and the correct door in the same question
In fact, the lying guard is a red herring. You get one question, and need one piece of info: the door. The canonical question doesn't tell you which guard lies, nor do you care to find out.
load more comments
(1 replies)