Murder Grid — Rules and Strategy
A daily deduction puzzle. Solve a 6×6 sudoku to earn evidence, use it to catch the two liars among five statements, and name the culprit, the room and the weapon.
The one-line version
Your sudoku skill is the currency you buy clues with. How well you solve the grid converts directly into how much information you have to reason with.
Core rules
- Solve the grid. It is a 6×6 sudoku. Pick an empty cell and place 1–6. Digits cannot repeat within a row, a column, or a 2×3 box — same as ordinary sudoku.
- Completing a region opens an envelope. Every time you finish one row or one box, the envelope pinned to it is recovered. Inside is a piece of evidence.
- There are two kinds of evidence. Forensics narrows down the scene. An alibi eliminates one suspect — but only once you already know where and with what it happened.
- Catch the two liars. Each forensic result contradicts exactly one statement head-on — one about the room, one about the weapon. Whoever made a contradicted statement is lying.
- Name the culprit. The culprit is one of the two liars. Lock the room and the weapon using the three true statements, then read the alibis: one liar is eliminated and the other one did it.
Using the notebook
Tapping an entry in the suspect list cycles it through ruled out → prime suspect → unmarked. What matters is that the game will not mark anything for you. There is no auto-elimination, so the notebook is the only record of what you have actually established. Skip the marking and you will re-derive the same deduction twice in the endgame.
Strategy
1. Chase rows before boxes
Envelopes are pinned to both rows and boxes, but on a 6×6 grid a row usually closes before a box does. If you see a row that is already more than half full, fill that one first and bank the envelope early. Evidence that arrives early also makes the rest of the grid less stressful to solve.
2. An alibi is a card you re-read later
It is normal for an alibi to look meaningless when you first receive it. Before the room and weapon are locked, an alibi is undecidable. Do not discard the ones you get early — flag them, and once the room and weapon are fixed, go back and read every single one again. That is where the game is won or lost.
3. Pin the two liars first, think about the culprit second
Reverse the order and you will flounder. Starting from «who is the culprit» forces you to weigh all five statements at once, when the actual structure is two-stage: two liars → one of them. Lock the liars with your two forensic results and the field drops from five to two; after that a single alibi finishes it.
4. Treat the three true statements as settled fact
Once you have identified the two liars, the remaining three statements are all true. Use them to fix the room and weapon without second-guessing. Re-opening those doubts is throwing away information you already paid for.
5. Wrong accusations go on the record
A wrong call raises your mistake count and appears on the result card. Do not guess before you are sure — solving one more region and opening one more envelope is almost always the better move.
6. A new case discards the current one
«New mystery» throws away the case in progress and generates a fresh one. Hitting it out of habit whenever you feel stuck will break your streak. When you feel stuck, there is usually still a cell on the grid that can be determined.
FAQ
Does the puzzle change every day?
Yes. The daily case is generated deterministically from the date, so everyone playing on the same day gets the same case. You can also pick a difficulty.
Can a case have more than one answer?
No. Before release we verify a full year of cases to confirm that (a) the sudoku solution is unique and (b) the culprit, room and weapon are each uniquely determined.
Do I need an account?
No. Your history is stored in your browser only and is never sent to a server.
Does sharing my result spoil the answer?
It does not. The share card contains only which regions you solved and how many mistakes you made — never the culprit, room or weapon.
Is there a tutorial?
Yes. On first open, training case CASE #000 walks through the full rule set once.
Design note — why there is no auto-elimination
Marking suspects in the notebook is something the game could have done for you. When an alibi rules someone out, it could simply strike their name. That was left out deliberately.
Auto-elimination changes what the player is doing — from reading evidence and judging to watching the screen cross things off. The hand solving the grid and the head doing the deduction come apart, and the premise of the game (that sudoku skill is the currency you buy clues with) collapses with them. If marking ever feels like a chore, that is the signal that you are actually reasoning right now.
For the same reason, nothing ever pops up to say «this statement is false». Spotting the contradiction is the game.
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This page is updated whenever the rules change. If you spot an error, tell us through contact.