How to play a logic grid puzzle
A logic grid puzzle hands you a row of numbered positions, a handful of clues, and exactly one arrangement that satisfies all of them at once. Nothing is hidden and nothing is random. Everything you need is on the page in front of you.
This is the whole rulebook for Verdict, a daily detective version of that puzzle. It takes a few minutes to read, there is a worked example at the bottom, and you only have to read it once.
01 · THE SETUP
One case a day.
Verdict opens three fresh cases every day, at Easy, Medium and Hard. A new set lands at midnight where you are. A case is a row of numbered positions (rooms along a hall, compartments on a train, desks down an office floor), a cast of values to hand out among them, and a list of clues that fit together exactly one way. Everyone playing the same level gets the same case, and closing any one of the three keeps your streak alive.
02 · THE GOLDEN RULE
Everything fits exactly one spot.
Every name, drink, item and time belongs to exactly one position, and every position holds exactly one of each. No repeats, and no blanks in a finished board. If Leo is in Compartment 3, nobody else is in Compartment 3 and Leo is nowhere else. Most deductions come from this rule colliding with a clue: the moment a value is filed, it is off the table everywhere else, and that is usually what forces the next placement.
03 · THE BOARD
Cards, slots, values.
The board is one numbered card per position, stacked top to bottom. Each card carries one slot per category, left to right, under the column headings that name those categories. A value is one entry that goes in a slot: a guest, a drink, an item, a time. The clues are your case notes, numbered so a hint can point at one. On a wide screen they sit beside the board; on a narrow one they sit under it. That is the whole vocabulary: card, slot, value, clue.
04 · FILING A VALUE
Click a slot, then click a value.
Click a slot on a numbered card, then click a value to file it. The picker opens inside that same card so your eye never leaves the row you are working on. A value already filed elsewhere is shown with a return arrow, and filing it here moves it rather than duplicating it, because of the golden rule. Clear empties the slot again, and Undo, under the board, reverses any move one step at a time.
05 · RULING OUT
Eliminations are how detectives actually work.
Switch the picker from Place to the pencil, Rule out, and clicking a value marks it as something this slot cannot be instead of filing it there. Ruled out values read struck through, and an empty slot stops showing dots and starts showing the initials of the values still in play. On a hard case this is the real work. You rarely learn where something goes first. You learn the three places it cannot go, and the fourth place is then forced.
06 · SWAPPING ROWS
Park a grouping, then slide it.
Often you work out that three values belong together long before you know which position they sit in. File them onto one card anyway, then click that card's number plate and another card's number plate to swap the two rows whole. The grouping travels intact, so a partial answer can wait on the board instead of in your head.
07 · THE VERDICT
The case notes keep score.
Each clue turns ✓ the moment your placements satisfy it, and red ✗ the moment they break it. An unmarked clue is one your board has not said anything about yet. When every clue is satisfied and every slot is filled, the case closes, the file is stamped CASE CLOSED with your time, and your streak grows. A red clue is not a penalty, it is the fastest information on the board: something you filed is wrong, and the ✗ names the clue that caught it.
08 · THE HINTS
Stuck is a step, not a wall.
Hint reads your actual board and answers in tiers, so you can take the smallest push that unsticks you:
- The first press names the clue worth re-reading, or the row worth looking down, and nothing else.
- Still stuck? Show more explains what that clue does against what you have already placed, and asks you where the value must go.
- One more press gives the deduction outright: the single next placement, and what forces it, whether that is a clue or the fact that no other position is left. It stops there. It never fills the rest of the board and it never asks you to guess.
- If your placements already contradict each other, the hint says so instead. It names the cell to clear when it can tell which one is at fault, and names the pair that clash when either could be.
09 · THE GUARANTEE
No guessing, ever.
Before a case is ever published, a solver that uses only techniques a person can use has to finish it. If that solver has to guess at any point, the case is thrown out and a different one is generated in its place. So when you are stuck, a deduction is always available from what is already on the board and you simply have not found it yet. That is a property of the puzzle, not encouragement.
10 · THE WORKED CASE
A worked example, start to finish.
Three rooms along a hall. Three guests: Ava Sterling, Clara Voss, Felix Marsh. Three drinks: brandy, port, earl grey. Each guest was in a different room with a different drink. These are the case notes:
- 1. Ava Sterling was in Room 2.
- 2. The guest drinking the brandy was in the room right before Ava Sterling.
- 3. Clara Voss and the guest drinking the earl grey are the same person.
The chain
- Clue 1 is a direct placement. Click the Guest slot on card 2, click Ava Sterling, and she is filed in Room 2.
- Clue 2 says brandy sits in the room right before Ava. Ava is fixed in Room 2, so the room right before her is fixed too. File brandy in the Drink slot of Room 1. Nothing was guessed there, it was read off the board.
- Clue 3 gives Clara the earl grey. Room 2 already holds Ava, so Clara is not in Room 2. Room 1 already holds the brandy, and Clara drinks earl grey, so she is not in Room 1 either. Rule her out of both. Room 3 is the only room left, so Clara Voss and the earl grey go in Room 3.
- The golden rule collects the leftovers. Felix Marsh is the only guest with no room, so he takes Room 1, next to the brandy already filed there. Port is the only drink left, so it goes to Ava in Room 2. The board is full.
| Room | Guest | Drink |
|---|---|---|
| Room 1 | Felix Marsh | brandy |
| Room 2 | Ava Sterling | port |
| Room 3 | Clara Voss | earl grey |
Every clue now reads ✓ and every slot is filled, so the case closes. A published case is bigger: Easy is four positions across three categories, Hard is five positions across four, and the clues lean more on order than on outright placement. The moves never change. File what a clue forces, rule out what it forbids, and let the golden rule take the leftovers.
Open a case.
Three cases are open right now at Easy, Medium and Hard. Easy is the four position board, and it is the one to read the manual against. Nothing here needs an account, and a hint costs nothing but a line in the file.
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