Murder mystery sudoku takes the most popular logic puzzle in the world and gives it a reason to exist beyond the grid. Somewhere, a victim has been found dead. Six people had a motive. The sudoku holds the evidence, and when you solve it, the numbers tell you who did it, what they used and where it happened.
This guide explains how a case works on Daily Whodunit, how to read the evidence, and a few tips to help you close your first case without wasting an accusation.
How a case is put together
Every case has four parts.
- The scene. A short report sets the stage: a country manor cut off by a storm, a sleeper train in the Alps, a theatre after opening night. It names the victim and the time of death.
- The suspects, weapons and locations. Three numbered lists, each from 1 to 6. One suspect, one weapon and one location are guilty.
- The grid. A classic 9×9 sudoku with one solution. Three of its empty cells are outlined in red and marked S, W and L.
- The case file. Clues that tell you exactly where the evidence cells are, plus a few corroborating facts to check your answer.
Reading the evidence
Once the grid is solved, the cell marked S holds the suspect’s number, W holds the weapon’s number and L holds the location’s number. Match each one to its list. If the S cell holds a 4, the killer is suspect number 4. Put the three together and you have your accusation: the butler, with the bell rope, in the wine cellar.
The three numbers are always different and always between 1 and 6, because each list has six entries. The corroborating facts in the case file, such as “the location number is odd”, let you confirm your reading before you commit.
A worked example
Imagine a case set at Thornfield Manor. Sir Edmund Ashworth has been found dead in the manor while a storm cut the phone lines. The case file says the suspect is the number in row 4, column 5, the weapon is the number in row 9, column 4, and the location is the number in row 5, column 8.
You solve the grid and find a 6 in the suspect cell, a 2 in the weapon cell and a 5 in the location cell. Suspect 6 is Ned the Gardener, weapon 2 is the arsenic tea, and location 5 is the stables. Before accusing, you read the corroborating facts: the three numbers are all different, the weapon number is smaller than the suspect number, and the location number is odd. Everything agrees, so you accuse Ned the Gardener, with the arsenic tea, in the stables.
If one of the facts had not matched, that would be a sign of a mistake somewhere in the grid. Go back and check the rows, columns and boxes around the evidence cells before you spend an accusation.
Making the accusation
When you play online, you choose a suspect, a weapon and a location and press the button. You have three accusations. Get it right and the case is closed. Use all three without success and the case goes cold, and the answer is revealed.
Three tries is generous if you solve the grid properly, and deliberately tight if you try to guess. With six suspects, six weapons and six locations there are over a hundred possible combinations, so the only reliable way to win is to do the logic.
Tips for your first case
- Start on a Monday or Tuesday. Early-week cases have more starting numbers and only need basic techniques.
- Keep an eye on the evidence cells. You need the whole grid to be correct, but the three marked cells are what matter. Make sure their rows, columns and boxes are rock solid.
- Use Notes when you get stuck. Pencil marks turn a frustrating grid into a solvable one. Our guide to sudoku techniques for beginners explains how to use them.
- Check before you accuse. Read the corroborating facts in the case file and make sure your three numbers agree with every one of them.
- Hints are allowed. The Hint button fills in one ordinary cell for you. It never fills the evidence cells, so the final deduction is always yours.
Difficulty through the week
Cases follow a weekly rhythm. Monday and Tuesday are easy, Wednesday and Thursday are medium, Friday and Saturday are hard, and Sunday is a tricky one to round off the week. Harder cases start with fewer numbers and need longer chains of logic, such as spotting pairs of candidates.
Play online or on paper
You can solve every case in your browser, on a phone or a computer. Your progress is saved as you go, a timer runs in the corner, and when you close a case you can copy a spoiler-free result to share with friends.
If you prefer pencil and paper, press Print. You get a one-page case file with the grid, row and column numbers to make the clues easy to follow, tick-boxes to rule out the innocent, and space to write your accusation. The solution is printed upside down at the bottom.
Why it is so satisfying
A plain sudoku ends with a full grid. A murder mystery sudoku ends with a verdict. That small story changes how the puzzle feels: every number you place is a piece of evidence, and the last few cells carry real suspense. It is the same reason detective novels are hard to put down. You want to know who did it.
A new case opens every day at midnight, New York time. Play today’s case, or start with an easy one from the case archive.
Prefer to solve on paper first? Print our free printable starter pack: 15 murder mystery sudoku puzzles from easy to hard, with the answers included.