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Murdoku Playground

Elimination Strategies

Learn some effective elimination techniques for Murdoku puzzles.

  1. 1

    Single Remaining Cell

    If a row or column must contain a character and every other cell has been eliminated, the remaining cell necessarily contains some character (undetermined).

    Example 1
    BeforeSingle Remaining Cell before 1
    AfterSingle Remaining Cell after 1
    Example 2
    BeforeSingle Remaining Cell before 2
    AfterSingle Remaining Cell after 2
  2. 2

    One-Dimensional Positions

    If all valid positions for a character lie in a single row or column, all other characters can be removed from that row or column.

    BeforeOne-Dimensional Positions before 1
    AfterOne-Dimensional Positions after 1
  3. 3

    Square Intersection

    When a character has only two possible positions and they form a square pattern, you can eliminate intersections.

    BeforeSquare Intersection before 1
    AfterSquare Intersection after 1
  4. 4

    L Intersection

    When a character's possible positions form an L-shape, the intersection of those rows and columns can be eliminated for other characters.

    Example 1
    BeforeL Intersection before 1
    AfterL Intersection after 1
    Example 2
    BeforeL Intersection before 2
    AfterL Intersection after 2
  5. 5

    Cross Intersection

    When a character's positions form a cross or T pattern across a row and column, the intersection point can be eliminated for other characters.

    Example 1
    BeforeCross Intersection before 1
    AfterCross Intersection after 1
    Example 2
    BeforeCross Intersection before 2
    AfterCross Intersection after 2
  6. 6

    Locked Pair

    If two characters can only occupy the same two rows or columns, no other character can use those positions — eliminate every other character from those rows or columns.

    Example 1
    BeforeLocked Pair before 1
    AfterLocked Pair after 1
    Example 2
    BeforeLocked Pair before 2
    AfterLocked Pair after 2
  7. 7

    Full Area Occupancy

    If an area must contain exactly N characters and the area spans N rows or N columns, cells outside that area in those rows or columns can be eliminated. Examples: "Briana was only with Derek", "One of the rooms had two characters" (sometimes logical deduction is required).

    Example 1
    BeforeFull Area Occupancy before 1
    AfterFull Area Occupancy after 1
    Example 2
    BeforeFull Area Occupancy before 2
    AfterFull Area Occupancy after 2