In an imposter game, the spy's whole experience depends on one question: how much do they know? In Who's the Spy, the answer is the category and nothing more. The spy does not know the word, a hint, or the first letter. They know that it is, say, a food, or a place, or a job. That small amount of information is the engine of the game.
Why give the spy the category?
Because with nothing at all, the spy cannot play. If they knew nothing, their first clue would be pure luck and they would be caught in one lap. A category gives them a frame: whatever the word is, it belongs to this family. They can say something that fits the family and hope to fit the member.
Why not give them more?
Because with a hint, the spy would be hard to catch. The balance of the game depends on the spy being uncertain but not helpless. Category-only keeps them in that narrow, tense space.
What does the spy see?
The name of the category, and nothing else. They do not see the word. The word is held back from them, and from everyone who does not hold it, so that a caught spy's guess is worth something: it goes public only after the guess is made.
How does the spy use the category?
They narrow the field. A category such as animals contains many kinds; a clue such as "has legs" fits most. The spy listens for the first specific clue and uses it. If the first civilian says "fast", the spy considers fast animals and shapes their own clue to fit.
By the second lap, the spy has several clues and can usually reduce the field to a handful.
How does the category help the civilians?
It helps them recognise the spy. Players who know the word give clues that sit inside the word's neighbourhood. A spy gives clues that sit inside the category's much larger neighbourhood. The difference in specificity is the strongest evidence the civilians have.
What is the effect of narrow and broad categories?
A narrow category, such as jobs and professions, produces clues that cluster. A broad one, such as household objects, produces a wide spread of clues. Narrow categories are harder for the spy: there is less room to hide. Broad ones are easier for the spy and more confusing for civilians. A host can choose the mix.
What does a caught spy know?
After the vote, a caught lone spy sees ten options from the category, the real word among nine decoys. Now they use everything they heard. Their knowledge has grown from a category to a field of clues, and they choose.
How do real tables use it?
Good spies play a quiet game of elimination in their heads. After each clue they ask which members of the category it could describe, and cross out the ones it cannot. Good civilians play the opposite game: they ask what the spy would say next, and give a clue that would be hard to copy. The category is the shared board on which both games are played.
It is also what makes a first-time spy feel less lost. Knowing the category, even a broad one, is enough to start speaking, and the first two clues from civilians fill in the rest.
What is the lesson for the civilians?
Say enough to prove you know, and no more. Every clue also teaches the spy.
Where can you see it in play?
At Boardit, a free site where you can play who's the spy with friends as a spy game online, the category is shown to the spy at the start of each round. Try to play one round as the spy and note what you do with the category.
The right amount of information
A little information is worse than none, or better than all. The category sits in exactly the right place.
Ahmed Moaz builds Boardit, a free browser game site.