The Black Files · Rules
How to play The Black Files
Seven people were at the scene. One of them is dead. Use the evidence to place everyone on the map, and find out who was alone with the victim.
The rules
- One person per row and one per column. The 7×7 grid holds exactly seven people, the victim included, so every row and every column has exactly one.
- Dark squares are objects. Each one shows its name (a safe, a door, a truck…). Nobody can be there.
- Stand on any empty square or on stairs, or sit on a chair or sofa. Someone sitting is on a chair or sofa; someone standing on the floor is on an empty square; someone on stairs is on a stairs square.
- The map has four zones (rooms), each with its own colour, pattern and name, separated by thick lines. "Next to" means up, down, left or right inside the same zone.
- The crime-zone rule. The killer was alone with the victim: the victim's zone holds exactly two people, the victim and the killer.
- All evidence is true. North is up, west is left. "Farther north than" compares rows only; "farther west than" compares columns only. The victim counts in every clue ("the easternmost person" can be the victim).
The victim and the killer
The victim is marked on every case. You don't need a motive or a weapon: once all seven people are placed, the killer is simply the only other person in the victim's zone. That is why the crime-zone rule is also a powerful clue. If a zone already has two people in it and neither is the victim, the victim must be somewhere else.
Why there is exactly one answer
Every Black File is checked by a solver before it is published: the evidence allows exactly one arrangement of the seven people. You never need to guess. If you feel stuck, some clue still has something to tell you, often combined with the one-per-row and one-per-column rule. Harder ranks ask you to test a hypothesis ("if Beth were in row 2…") and follow it until it breaks.
Controls
- Pick a person (A–G), then tap a square to place them. Tap them again to remove them.
- Use ✕ Rule out to cross off squares you have eliminated.
- Use ✎ Notes to pencil in possible people: pick a person, turn Notes on and tap squares. A square can hold several small letters, so you can test ideas before committing.
- Crosses and notes are optional helpers. Check only looks at the seven people you have placed.
- Tap a clue to strike it through once you have used it.
- Stuck? Hint reveals the next step. Hints are counted in your result.
- When all seven are placed, press Check. On a keyboard: A–G choose a person, X rules out, N toggles notes, Ctrl+Z undoes.
The eight ranks
| # | Rank | What to expect |
|---|---|---|
| 01 | CADET | Direct clues only. Each placement pulls the next one along. |
| 02 | ROOKIE | Negative clues join in: what a statement rules out matters as much as what it confirms. |
| 03 | INVESTIGATOR | Compass clues fix whole rows and columns. Let the clues interact before you commit anyone. |
| 04 | DETECTIVE | Count heads per zone and use the crime-zone rule early. |
| 05 | SENIOR DETECTIVE | Elimination alone won't close it: test a placement and follow it to a contradiction. |
| 06 | SPECIALIST | Choose whom to test. The person with the fewest possible squares breaks the board fastest. |
| 07 | ELITE | No safe opening move: you reason by contradiction from the start. |
| 08 | MASTER DETECTIVE | Everything at once and no guidance. You are alone with the evidence. |
Every past case is in the archive, with a step-by-step solution. A new case opens every day.
