Sleuth

About this board game

Sleuth is a deduction game for 3–7 players, played in about 45 minutes, in which you investigate clues to identify one hidden gem card. Originally released in 1971, it challenges players to reason from both what they learn and what remains unknown.

Before play begins, one of 36 gem cards is hidden. Each gem card shows 1–3 diamonds, pearls, or opals in one of four colors. The remaining cards are dealt among the players, with any leftover cards placed face up, giving everyone useful information about what the missing card cannot be.

On your turn, choose one of your four face-up search cards and ask an opponent how many cards they hold matching its element. Questions can concern broad categories, such as pairs, or more specific details, such as red diamonds or blue opals. For a specific question, the opponent reveals the number of matching cards and lets you inspect them in secret; broader questions provide a number without showing which cards qualify.

• Track positive and negative information on a score pad.
• Use 54 search cards featuring one or two elements.
• Ask questions, compare answers, and eliminate possibilities.
• Make a guess at any time, or ask one unrestricted question on your turn before guessing.

A wrong guess does not immediately remove you from the game, but from then on you may only answer questions. A correct guess wins, making every deduction and every question matter. The simple rules conceal a demanding puzzle: sometimes you see cards, while other times you receive only a count.

In Sleuth, careful notation and flexible reasoning help transform scattered clues into a single solution. It reimplements The Case of the Elusive Assassin, using its core mechanisms without the board, movement, or player proximity.