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What Is a Murder Sudoku? Rules, Tips and Where to Play
A murder sudoku is a logic puzzle where you place suspects on a floor plan, one per row and column, to find the killer. Here are the rules, solving techniques and where to play free.
"Murder sudoku" is the nickname for a newer kind of logic puzzle that mixes a sudoku-style placement rule with a whodunit. Instead of digits you place people; instead of a 9×9 box grid you get a floor plan with rooms and furniture; and the last deduction gives you a name — the killer's.
The format was popularised by Manuel Garand's Murdoku books, and it's now played in several forms, including our free daily game. Here's how it works.
The rules
Almost every murder sudoku uses some version of these:
- One person per row and per column. This is the sudoku part — no two suspects share a row or a column.
- Furniture matters. Some squares can't be stood on (tables, plants, shelves); others can (chairs, sofas, beds, rugs).
- The statements are true. Each suspect tells you something about where they were: beside the piano, in the kitchen, in a corner, alone, north of someone.
- The killer was alone with the victim. When everyone is placed, the one person sharing a room with the victim did it.
Variants add twists — in ours, the killer lies on Sundays.
A worked example
Four suspects, two rooms. One statement fits only one square, which fills a row and a column; that removes options for the next suspect; and the chain continues until the last person — the victim — drops into the only free square. Whoever shares their room is the killer.
Solving techniques
- Start with the most restrictive statement. "Beside the stove" may fit two squares; "in the living room" twelve.
- Cross out rows and columns immediately after each placement.
- Count room capacity. A room spanning two rows and three columns can hold at most two people.
- Use the victim rule early. The victim's room must hold exactly two people — rooms that can't fit a second person are ruled out for the victim.
- For lying-killer puzzles, assume each suspect in turn is the liar; only one assumption leads to a consistent plan.
Where to play
- Free, every day: a new floor-plan murder mystery at Room for Murder Daily — small 5×5 houses on Mondays up to 7×7 mansions on Saturdays.
- Printable, free: five cases from our book when you join the Case Club (box at the bottom of the home page).
- Books: the Murdoku series, and our own Room for Murder with 80 cases.
Room for Murder
80 floor-plan murder mysteries in five chapters, from cosy cottages to a lying-killer finale — the book behind this site.
Solo or together
See it on Etsy
Room for Murder Daily
A new floor-plan murder mystery every morning: place the suspects, find who was alone with the victim. No sign-up, works on phones.
Play today's caseWe make the games mentioned in this guide — that's why we know them well. Links to Etsy go to our own shop, Midnight Motive.
Murdoku is a trademark of its owner. Room for Murder is an independent game and is not affiliated with or endorsed by the Murdoku books or their publishers.