Sudoku Detective
How to play Sudoku Detective
A murder, a floor plan and a handful of suspects. Each of them says where they were; you place them. When the plan is full, the murderer is whoever was left alone with the victim. It takes two minutes to learn.
The rules, in four steps
One per row and per column
Like a sudoku. Nobody on the shaded squares.
No two people can share a row or a column, just like in a sudoku. And nobody stands on a square taken up by furniture: those squares are shaded and out of play.
Each card says where they were
“Next to” means adjacent and in the same room: walls cut.
Every suspect signs a card saying where they were: in a room, next to an object, in a row, or beside someone else. What they say is true — except in cases with a liar, and those are flagged at the top. “Next to” means the adjacent square and in the same room: walls cut, even where the squares touch.
Alone with the victim
Place everyone. Whoever shares a room with the victim is the murderer.
Place everyone, the victim included. When the plan is full, look at the victim's room: whoever is in there with them is the murderer. There is always exactly one.
Tap to note, hold to place
Card first, then square. Stuck? Ask for a hint.
Tap a card and then a square to pencil in a note; press and hold to place the token. With no card selected, a tap crosses the square out. Submit tells you how many tokens are wrong, but not which ones; Hint reasons out the next safe step.
A case solved step by step
This is a real case, one of the easy ones. Step through it: each step places one person and explains why there and nowhere else. It is the same reasoning the Hint button gives you.
- Step 1
Bruno was next to a sarcophagus. By her card, Diana must be in row 2. Row 5, column 2, in the Camp.
- Step 2
Diana was in the Passage. Rule out the rows and columns of Bruno. Row 2, column 1, in the Passage.
- Step 3
Alice was sitting on a stool: only one square fits. Row 1, column 5, in the Pillared Court.
- Step 4
Carmen's card is about others, not about her own square. Rule out the rows and columns of Diana, Bruno and Alice. She was southwest of Victor, and Victor can only be in row 3, column 4. Row 4, column 3, in the Stairwell.
- Step 5
Victor, the victim, has no card. Rule out the rows and columns already taken. Row 3, column 4, in the Stairwell.
And the murderer is…
With everyone in place, only one person is left in the same room as the victim. The murderer was Carmen.
Frequently asked questions
Do I need to know how to play sudoku?
No. Only one rule comes from sudoku: one person per row and one per column. The rest is deduction from what the cards say.
What does “next to” mean?
Adjacent — above, below, left or right, never diagonally — and in the same room. Two squares that touch but are split by a wall are not next to each other.
What if I get it wrong?
Nothing is lost. Submit tells you how many people are in the wrong place, but not who. If you want to know who, ask for a hint: that one does say.
Is it free? Do I need an account?
It is free: no account, no downloads, no ads. Your game is saved in your browser, so you can close it and pick it up later on the same device.
How many cases are there?
Forty cases are open at any one time; every Monday three new ones arrive and the three oldest leave. The book has ninety more, with step-by-step solutions.
Shall we?
Forty cases are open right now, and every Monday three new ones arrive and three leave.