The best way to learn Hearsay is to watch a case get solved. This one is a real Monday board, with nine people and one rule, and every step below is something you can prove. There's no guessing anywhere in it.
The board
Nine people in a 3 by 3 grid. Columns are lettered and rows are numbered.
A B C 1 Ada (pilot) Bram (pilot) Cleo (clerk) 2 Dex (guard) Edie (guard) Finn (clerk) 3 Gwen (pilot) Hugo (guard) Iris (pilot)
The rule: every column has exactly one liar. Hugo is revealed as honest to start. Here's what everyone says:
- Ada: Dex and I are opposite: one honest, one a liar.
- Bram: Ada and I are the same: both honest or both liars.
- Cleo: Edie and I are opposite: one honest, one a liar.
- Dex: Gwen has exactly 1 liar neighbor.
- Edie: All 3 guards are liars.
- Finn: Iris and I are the same: both honest or both liars.
- Gwen: All 4 pilots are honest.
- Hugo: There are exactly 3 honest people in row 3.
- Iris: I have exactly 1 honest neighbor.
Step 1: start with the person you know
Hugo is honest, so what he says is true. There are exactly 3 honest people in row 3, and row 3 has exactly 3 people. So Gwen, Hugo and Iris are all honest. One clue just gave us two marks.
Step 2: use the honest person's clue
Gwen is honest and says all 4 pilots are honest. The pilots are Ada, Bram, Gwen and Iris. So Ada and Bram are honest too.
Step 3: the "me and someone else" trick
Ada is honest, and she says exactly one of Dex and herself is a liar. That's true. Ada isn't a liar, so Dex is a liar.
This one works either way. Even if Ada had been lying, the same statement would have made Dex a liar too. Anyone who says "exactly one of X and me is a liar" settles X.
Step 4: use the rule
Column B is Bram, Edie and Hugo. The rule says exactly one of them is a liar. Bram and Hugo are honest, so Edie is the liar.
Edie said all 3 guards are liars. That's false, which is what a liar does. The Truth line would read "at least one of the 3 guards is honest", and Hugo is a guard who is honest. It fits.
Step 5: read a neighbor count
Iris is honest and has exactly 1 honest neighbor. Her neighbors are Edie, Finn and Hugo. Hugo is honest and Edie is a liar. For the count to be exactly 1, Finn can't be honest. So Finn is a liar.
Step 6: finish with the rule
Column C is Cleo, Finn and Iris. Exactly one is a liar, and it's Finn. So Cleo is honest. Cleo says exactly one of Edie and herself is a liar. Edie is a liar and Cleo isn't, so that's true.
The result
- Honest: Ada, Bram, Cleo, Gwen, Hugo, Iris
- Liars: Dex, Edie, Finn
One liar in each column, as the rule says. And every liar's clue turns out to be false. Dex said Gwen has exactly 1 liar neighbor, but her neighbors Dex and Edie are both liars, so it's 2. Finn said he and Iris are the same kind, and they aren't.
What to take away
- Start with someone you know. The revealed person's clue is always true, and it's often your first move.
- Count what's left. A rule like "one liar per column" turns every honest person into information.
- Look for the "me and someone else" clue. It gives you a free mark.
- Check your answer against the liars. If a liar's clue came out true, something is wrong.
Later in the week the boards are bigger, and you'll sometimes need two clues at once. The how to play Hearsay guide covers every kind of clue. If you like this kind of puzzle, there's more in liar puzzles and knights and knaves.