Murder sudoku is sudoku with suspects: every row and column of a floor plan holds exactly one person, every statement is true, and the suspect alone with the victim did it. You can play 800 cases free in UnMask on iPhone and iPad.
What is murder sudoku?
A murder sudoku gives you a floor plan cut into rooms, a handful of suspects and one victim. Each suspect tells you something true about where they were: in the library, on the sofa, somewhere left of the piano. Like sudoku, every row and every column holds exactly one person. Place them all and one cell is left for the victim — and the only suspect in the victim's room is your killer.
Sudoku vs murder sudoku
If you can do a sudoku, you already know half the rules. Here is what changes.
| Rule | Sudoku |  Murder sudoku |
|---|---|---|
| The grid | 9×9 numbers in 3×3 boxes | A floor plan of rooms, 5×5 up to 12×12 |
| Each row and column | Holds every number once | Holds exactly one person |
| The clues | Numbers already filled in | True statements from every suspect |
| The goal | Fill every cell | Place everyone and name the killer |
Solve one, step by step
This is a real board from UnMask, halfway through a case at a grand hotel. Crosses mark the cells that can no longer hold anyone.
- 1
Start with the sure things
A statement like “I was on the bed” often pins a suspect to a single cell. Place them first.
- 2
Cross out their row and column
Nobody else can stand in that row or column — exactly the move you make in sudoku.
- 3
Find the last place left
When a suspect has one possible cell left, they go there. Repeat until the victim's cell is the only one remaining; the suspect in that room did it.
Murdoku, Murdle and UnMask
If you searched for “murdoku”, you were most likely looking for murder sudoku — the name has stuck to the format. Murdle, the puzzle series by G.T. Karber, is a cousin: it uses a deduction grid of suspects, weapons and places instead of a floor plan. UnMask sits closest to murder sudoku, with a story around every case and hints that explain the next step.
To be clear: UnMask is its own game. It is not affiliated with any book, app or brand called Murdoku or Murdle.
Where to play murder sudoku
UnMask puts murder sudoku in your pocket: free to download, made for iPhone and iPad, and it works offline.
- 800 free cold cases, from 6×6 to 12×12
- Story cases with a cast, a motive and a twist
- Hints in three steps: a nudge, the reasoning, the move
- Progress synced between iPhone and iPad
FAQ
What is murder sudoku?
A logic puzzle that borrows sudoku's rule — exactly one per row and per column — and swaps the numbers for suspects on a floor plan. Place everyone using their statements, and the one suspect who shares a room with the victim is the killer.
Is murder sudoku the same as Murdoku?
“Murdoku” is a name many people use for murder sudoku. UnMask plays by the same idea, but it is its own game and is not affiliated with any book or app called Murdoku.
Can I play murder sudoku online?
UnMask is an app rather than a website: download it free on iPhone or iPad and play 800 murder sudoku cases, which keep working offline.
Is murder sudoku hard?
It scales. Beginner cases on a 5×5 board teach the row-and-column trick in a few minutes; Expert cases and 12×12 cold cases ask you to think several moves ahead.
