Murder mystery sudoku — the daily cases for 31 July 2026

Every detective in the world got these same crime scenes on 2026-07-31 — each difficulty published twice, once untimed and once as time attack. Each case is procedurally generated and then proved to have exactly one logical solution before it is published, including the cases where somebody is lying. You place every suspect back on the map using only their testimony: exactly one person per row, never two in a column. Whoever is left alone with the victim did it.

Beginner — Blackbriar Manor

A 5×5 grid across 4 rooms: Conservatory, Ballroom, Cellar, Library. Five statements, three squares nobody could stand on, and no assumption anywhere: elimination alone closes it.

Cracked by 2 detectives so far.

How this case was cracked — the full solution to this board, step by step

Every step below is the solver’s own — the same one that proved this board has exactly one answer. The counts are real: you can check them against the grid.

The testimony

What each person said, and how much of the board it rules out.

Beatrix was in the cellar. leaves 5 of 22 squares
Show it on the board
The squares this one statement leaves Beatrix: 5 of 22.
Ines was in column 2. leaves 5 of 22 squares
Show it on the board
The squares this one statement leaves Ines: 5 of 22.
Ines was in the conservatory. leaves 1 of 22 squares
Show it on the board
The squares this one statement leaves Ines: 1 of 22.
Sol was in the ballroom. leaves 5 of 22 squares
Show it on the board
The squares this one statement leaves Sol: 5 of 22.
Alistair was beside the chest. leaves 1 of 22 squares
Show it on the board
The squares this one statement leaves Alistair: 1 of 22.

Show the squares Beatrix had left

The squares still open to Beatrix once their own statements are taken into account — 5 of 22.

What the testimony settles on its own

Nobody shares a row or a column, so each placement narrows everyone else. Before a single guess:

Beatrix can only be in Cellar (row 5, column 3) — down from 5 possible squares.
Sol can only be in Ballroom (row 2, column 1) — down from 5 possible squares.
Ruby can only be in Conservatory (row 3, column 5) — down from 22 possible squares.

The answer

That leaves one arrangement, and one person who could have done it: Ines, in Conservatory (row 1, column 2).

Show the solved board

The only arrangement the testimony allows. Ines is ringed in red.

Easy — The Night Express

A 6×6 grid across 4 rooms: Galley, Sleeper, Baggage, Observation. Eight statements, six squares nobody could stand on, and no assumption anywhere: elimination alone closes it.

Cracked by one detective so far.

How this case was cracked — the full solution to this board, step by step

Every step below is the solver’s own — the same one that proved this board has exactly one answer. The counts are real: you can check them against the grid.

Lettered squares are objects. Most take the square out of play — which is why the counts above are of free squares, not of all of them — but the ones marked below do not: their square is still in play. CH — chest · CR — crate · D — desk · M — mirror (square stays free) · P — painting (square stays free) · S — stove

The testimony

What each person said, and how much of the board it rules out.

Margot was in the baggage car. leaves 6 of 30 squares
Show it on the board
The squares this one statement leaves Margot: 6 of 30.
Margot was in row 3. leaves 1 of 30 squares
Show it on the board
The squares this one statement leaves Margot: 1 of 30.
Hugo was beside the crate. leaves 1 of 30 squares
Show it on the board
The squares this one statement leaves Hugo: 1 of 30.
Ines was in the rightmost column. leaves 6 of 30 squares
Show it on the board
The squares this one statement leaves Ines: 6 of 30.
Ines was beside the chest. leaves 1 of 30 squares
Show it on the board
The squares this one statement leaves Ines: 1 of 30.
Ruby was beside the desk. leaves 1 of 30 squares
Show it on the board
The squares this one statement leaves Ruby: 1 of 30.
Dorian was in the observation car. leaves 13 of 30 squares
Dorian was in column 5. leaves 2 of 30 squares

Show the squares Dorian had left

The squares still open to Dorian once their own statements are taken into account — 2 of 30.

What the testimony settles on its own

Nobody shares a row or a column, so each placement narrows everyone else. Before a single guess:

Sol can only be in Baggage (row 4, column 4) — down from 30 possible squares.
Dorian can only be in Observation (row 1, column 5) — down from 2 possible squares.

The answer

That leaves one arrangement, and one person who could have done it: Margot, in Baggage (row 3, column 3).

Show the solved board

The only arrangement the testimony allows. Margot is ringed in red.

Medium — The Night Express

A 7×7 grid across 5 rooms: Platform, Observation, Dining, Saloon, Baggage. Nine statements, nine squares nobody could stand on, and no assumption anywhere: elimination alone closes it.

Cracked by one detective so far.

How this case was cracked — the full solution to this board, step by step

Every step below is the solver’s own — the same one that proved this board has exactly one answer. The counts are real: you can check them against the grid.

Lettered squares are objects. Most take the square out of play — which is why the counts above are of free squares, not of all of them — but the ones marked below do not: their square is still in play. A — armchair (square stays free) · B — bed (square stays free) · CH — chest · CR — crate · D — desk · F — floor lamp · G — grandfather clock · P — painting (square stays free) · S — stove

The testimony

What each person said, and how much of the board it rules out.

Enzo was beside the painting. leaves 2 of 40 squares
Show it on the board
The squares this one statement leaves Enzo: 2 of 40.
Enzo was in the same room as Vivienne.
Vivienne was in the same column as the chest. leaves 6 of 40 squares
Show it on the board
The squares this one statement leaves Vivienne: 6 of 40.
Hugo was beside the crate. leaves 1 of 40 squares
Show it on the board
The squares this one statement leaves Hugo: 1 of 40.
Sol was beside the armchair. leaves 2 of 40 squares
Show it on the board
The squares this one statement leaves Sol: 2 of 40.
Sol was in the same row as the painting. leaves 1 of 40 squares
Show it on the board
The squares this one statement leaves Sol: 1 of 40.
Beatrix was in the observation car. leaves 7 of 40 squares
Show it on the board
The squares this one statement leaves Beatrix: 7 of 40.
Beatrix was in the same row as the desk. leaves 2 of 40 squares
Celeste was in the same row as the floor lamp. leaves 6 of 40 squares

Show the squares Enzo had left

The squares still open to Enzo once their own statements are taken into account — 2 of 40.

What the testimony settles on its own

Nobody shares a row or a column, so each placement narrows everyone else. Before a single guess:

Enzo can only be in Dining (row 7, column 2) — down from 2 possible squares.
Margot can only be in Saloon (row 2, column 4) — down from 40 possible squares.
Vivienne can only be in Dining (row 5, column 7) — down from 6 possible squares.
Beatrix can only be in Observation (row 1, column 1) — down from 2 possible squares.
Celeste can only be in Platform (row 3, column 6) — down from 6 possible squares.

The answer

That leaves one arrangement, and one person who could have done it: Hugo, in Saloon (row 4, column 3).

Show the solved board

The only arrangement the testimony allows. Hugo is ringed in red.

Hard — The Old Observatory

An 8×8 grid across 6 rooms: Workshop, Terrace, Lounge, Archive, Dome, Office. Eleven statements, ten squares nobody could stand on, and one round of assume-and-test after elimination ran dry.

Cracked by one detective so far.

How this case was cracked — the full solution to this board, step by step

Every step below is the solver’s own — the same one that proved this board has exactly one answer. The counts are real: you can check them against the grid.

Lettered squares are objects. Most take the square out of play — which is why the counts above are of free squares, not of all of them — but the ones marked below do not: their square is still in play. A — armchair (square stays free) · B — bookshelf · CH — chest · CR — crate · D — desk · F — floor lamp · G — grandfather clock · P — potted plant · S — statue · T — telescope

The testimony

What each person said, and how much of the board it rules out.

Margot was in the same room as Celeste.
Margot was not touching the outer wall. leaves 30 of 54 squares
Dorian was exactly 3 columns east of Enzo.
Dorian was in the same row as the potted plant. leaves 5 of 54 squares
Show it on the board
The squares this one statement leaves Dorian: 5 of 54.
Hugo was all alone in a room.
Ines was somewhere south of Margot.
Ines was exactly 3 columns east of Hugo.
Alistair was in the same row as the crate. leaves 7 of 54 squares
Show it on the board
The squares this one statement leaves Alistair: 7 of 54.
Alistair was in the same column as the floor lamp. leaves 1 of 54 squares
Show it on the board
The squares this one statement leaves Alistair: 1 of 54.
Celeste was somewhere east of Margot.
Celeste was in the same row as the floor lamp. leaves 7 of 54 squares
Show it on the board
The squares this one statement leaves Celeste: 7 of 54.

Show the squares Dorian had left

The squares still open to Dorian once their own statements are taken into account — 5 of 54.

The squares that had to be tested

The rest does not fall out on its own. It takes 38 eliminations of the same move: put someone on a square, follow the consequences, and watch the board contradict itself.

Had Margot stood in Office (row 2, column 5), Dorian would have had nowhere left to stand. So not there.
Had Dorian stood in Office (row 2, column 8), Margot would have had nowhere left to stand. So not there.
Had Enzo stood in Archive (row 3, column 2), Celeste would have had nowhere left to stand. So not there.
Put Hugo in Archive (row 1, column 5) and the testimony cannot be satisfied at all. So not there.

Show what goes wrong

Suppose Margot stood on the dashed square. Dorian then has nowhere left to stand: every square still open to them is shaded out.

Another 34 squares fell the same way.

The answer

That leaves one arrangement, and one person who could have done it: Enzo, in Workshop (row 6, column 2).

Show the solved board

The only arrangement the testimony allows. Enzo is ringed in red.

Expert — Blackbriar Manor

A 9×9 grid across 8 rooms: Ballroom, Lounge, Kitchen, Foyer, Library, Cellar, Conservatory, Study. Nine statements, fourteen squares nobody could stand on, almost as many rooms as suspects, so a room claim nearly names a square, and two rounds of assume-and-test after elimination ran dry.

Cracked by one detective so far.

How this case was cracked — the full solution to this board, step by step

Every step below is the solver’s own — the same one that proved this board has exactly one answer. The counts are real: you can check them against the grid.

Lettered squares are objects. Most take the square out of play — which is why the counts above are of free squares, not of all of them — but the ones marked below do not: their square is still in play. A — armchair (square stays free) · B — bookshelf · CH — chest · CL — clock · F — floor lamp · H — harp · M — mirror (square stays free) · PA — painting (square stays free) · PI — piano · PO — potted plant · SO — stove · ST — statue

The testimony

What each person said, and how much of the board it rules out.

Ruby was exactly 1 column west of Alistair.
Dorian was exactly 6 rows south of Alistair.
Dorian was in the same column as the mirror. leaves 7 of 67 squares
Show it on the board
The squares this one statement leaves Dorian: 7 of 67.
Dorian was exactly 5 rows south of Ines.
Redmond was exactly 2 columns east of Celeste.
Redmond was all alone in a room.
Redmond was exactly 7 columns east of Hugo.
Celeste was exactly 5 rows south of Vivienne.
Exactly 3 people were in the library.

Show the squares Dorian had left

The squares still open to Dorian once their own statements are taken into account — 7 of 67.

The squares that had to be tested

The rest does not fall out on its own. It takes 155 eliminations across 2 rounds of the same move: put someone on a square, follow the consequences, and watch the board contradict itself.

Had Ruby stood in Library (row 1, column 1), Hugo would have had nowhere left to stand. So not there.
Had Hugo stood in Library (row 3, column 1), Vivienne would have had nowhere left to stand. So not there.
Had Redmond stood in Study (row 3, column 8), Vivienne would have had nowhere left to stand. So not there.
Had Ines stood in Library (row 2, column 1), Hugo would have had nowhere left to stand. So not there.

Show what goes wrong

Suppose Ruby stood on the dashed square. Hugo then has nowhere left to stand: every square still open to them is shaded out.

Another 151 squares fell the same way.

Ruby can only be in Conservatory (row 7, column 4) — down from 3 possible squares.
Hugo can only be in Library (row 4, column 1) — down from 2 possible squares.
Dorian can only be in Ballroom (row 8, column 9) — down from 2 possible squares.

The answer

That leaves one arrangement, and one person who could have done it: Dorian, in Ballroom (row 8, column 9).

Show the solved board

The only arrangement the testimony allows. Dorian is ringed in red.

How to read a case above

The grid size is the size of the crime scene, so a 10×9 expert case is a far larger search than a 5×5 beginner one — but the difficulty is really carried by the clues, not the square count. A beginner case tells you almost directly where somebody stood. An expert case tells you where somebody was not, three times, and expects you to do the rest — and on half of them one of those statements is a lie told to protect the killer. If a case lists a motive, naming the right person is not enough on its own; you have to prove why.

How to play · Solving cases with a liar · Techniques

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Every day's cases — the calendar · ← the cases for 30 July

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