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4×4 · 10 steps · difficulty 25.7

Bulldoku Level 31: Walkthrough & Solution

Step-by-step Bulldoku level 31 guide (4×4). One pup per color, row and column, no touching. Difficulty 25.7.

Play Level 31

Step-by-step logic

  1. 1. Step: mark X (line reservation)

    Several regions share the same rows or columns — other cells on those lines are impossible. Mark them with X.

    Board after step 1

  2. 2. Step: logical elimination

    Placing a pup on the trial cell would leave a region with no legal move. Mark that cell with X.

    Board after step 2

  3. 3. Step: logical elimination

    Placing a pup on the trial cell would leave a region with no legal move. Mark that cell with X.

    Board after step 3

  4. 4. Step: mark X in row 2

    The pink region is confined to row 2. Mark X on cells in that row that belong to other regions.

    Board after step 4

  5. 5. Step: logical elimination

    Placing a pup on the trial cell would leave a region with no legal move. Mark that cell with X.

    Board after step 5

  6. 6. Step: logical elimination

    Placing a pup on the trial cell would leave a region with no legal move. Mark that cell with X.

    Board after step 6

  7. 7. Step: place pup (row 2, column 4)

    After previous pups, row 2 has only one free cell — column 4. Place the pink region's pup here. Mark crosses along the row, column, and neighboring cells (see the board).

    Board after step 7

  8. 8. Step: place pup (row 4, column 3)

    After previous pups, column 3 has only one free cell — row 4. Place the yellow region's pup here. Mark crosses along the row, column, and neighboring cells (see the board).

    Board after step 8

  9. 9. Step: place pup (row 1, column 2)

    After previous pups, column 2 has only one free cell — row 1. Place the cyan region's pup here. Mark crosses along the row, column, and neighboring cells (see the board).

    Board after step 9

  10. 10. Step: place pup (row 3, column 1)

    After previous pups, column 1 has only one free cell — row 3. Place the mint region's pup here. Mark crosses along the row, column, and neighboring cells (see the board).

    Board after step 10

Final solution

All pups placed correctly: R1 C2, R2 C4, R3 C1, R4 C3

Solved board

Similar difficulty levels

FAQ

How do I solve Bulldoku level 31?
Follow the 10 steps above: find forced placements first, then mark impossible cells with X.
Where can I play level 31 online?
Click "Play Level 31" to open the free browser game with this exact board.

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