Language · English
Think like a detective
Five ways to
make progress.
A useful next step need not be a placement. Ruling out a few cells with certainty also brings you closer to the solution. Here is how to do that in Moredoku.
Explore five separate map fragments without spoilers for existing cases.
Reading the map
These are separate practice fragments, not complete puzzles. The notes show the possibilities considered in each example. Given placements are certain. Count rows from top to bottom and columns from left to right.
A = Amir · B = Bente · C = Cleo. Letters and outlines make the meaning clear without relying on colour.
01 · Rows and columns
Follow through a placement
A certain placement also helps with the other people. Each row and each column can contain only one person.
Bente is already placed in row 2, column 3.
Look at the notes on the map fragment. What can you now deduce with certainty?
Show the reasoning and result
Reason it through
- Bente occupies row 2 and column 3. Every other cell in that row and column is ruled out for everyone.
- Amir had six possible cells: columns 1 or 2, in rows 2, 3 or 4.
- His two notes in row 2 are eliminated. The four notes in rows 3 and 4 remain possible; there is no certain placement yet.
Conclusion
Six empty cells are ruled out for everyone; Amir has four possibilities left.
Remember: Remove only possibilities that are truly impossible. Four remaining notes are not four placements.
02 · Two conditions
Find where clues overlap
Apply both conditions together. A cell must satisfy both, not just one.
Amir was next to a tree. He was in one of the bottom two rows.
Look at the notes on the map fragment. What can you now deduce with certainty?
Show the reasoning and result
Reason it through
- The tree is in the garden at row 2, column 2. Next to means one cell horizontally or vertically, within the same area.
- Three garden cells are next to the tree: row 1 column 2, row 2 column 1 and row 3 column 2. The cell to the right of the tree belongs to the terrace, so it does not count.
- Of those three possibilities, only row 3, column 2 is in the bottom two rows. That is where Amir belongs.
Conclusion
Place Amir in row 3, column 2.
Remember: Next to does not mean diagonally next to. Ignore an area boundary only when a clue explicitly allows it.
03 · Counting people
A full room rules out cells
Count the people who are already certain to be in a room. A full area can eliminate several notes at once.
There were exactly two people in the lounge.
Look at the notes on the map fragment. What can you now deduce with certainty?
Show the reasoning and result
Reason it through
- Bente and Cleo are already certainly placed in the lounge. Together they account for the stated total of two people.
- Nobody else can be in the lounge. Remove Amir's notes at row 2 column 2 and row 4 column 2. Those cells had not already been ruled out by Bente's and Cleo's rows or columns.
- Amir has two possibilities left in the hall. The victim cannot be in the lounge either: a general count of people includes the victim.
Conclusion
Rule out the remaining lounge cells for everyone still to be placed.
Remember: Two people does not automatically mean the culprit and victim. They can be two suspects, as in this example.
04 · Grouping possibilities
Reserve two columns for two people
You may not know someone's exact cell yet, but you can still know something certain about a group.
Amir and Bente can each only be in column 1 or column 3.
Look at the notes on the map fragment. What can you now deduce with certainty?
Show the reasoning and result
Reason it through
- Earlier clues have already narrowed the notes: Amir has two possible cells, and so does Bente. All their possibilities are in column 1 or column 3.
- They cannot share a column. Therefore one must occupy column 1 and the other column 3, whichever cells eventually prove correct.
- Cleo cannot be in either column. Remove her notes at row 2 column 3 and row 3 column 1. Keep her other three notes.
Conclusion
Remove Cleo's two notes in columns 1 and 3 without placing Amir or Bente yet.
Remember: This works only if you are certain that neither Amir nor Bente has any possibility outside those two columns.
05 · A chain of deductions
Follow the effects to the next person
A new placement can lead to another through a different clue. Reread the relevant clues after each placement.
Amir was exactly one row north of Bente.
Look at the notes on the map fragment. What can you now deduce with certainty?
Show the reasoning and result
Reason it through
- Cleo is certainly placed in row 4, column 2. That rules out row 4, column 4 for Bente.
- Bente had only one other possibility: row 2, column 3. Place her there.
- Amir must be exactly one row higher, in row 1. Of his two notes, only row 1, column 1 remains. Place Amir there.
Conclusion
One elimination gives two certain placements: first Bente, then Amir.
Remember: One row north specifies the difference in row number. It does not mean the two people are in the same column.
Back to your own case
From one certainty to the next
Read the general clues first. Mark possibilities, follow through the effects of every certain placement and revisit relationships between people. Stuck? A hint can explain the next deduction.
Four unsolved cases are open at each level. Solve one to open the next drawer. You can replay solved cases. These examples do not change your progress.