Bulldoku Level 840: Walkthrough & Solution
Step-by-step Bulldoku level 840 guide (10×10). One pup per color, row and column, no touching. Difficulty 70.3.
Play Level 840Step-by-step logic
1. Step: place pup (row 10, column 10)
After crosses, the cyan region has only one legal cell — row 10, column 10. Place a pup there. Mark crosses along the row, column, and neighboring cells (see the board).
Board after step 1 2. Step: place pup (row 2, column 9)
After crosses, the pink region has only one legal cell — row 2, column 9. Place a pup there. Mark crosses along the row, column, and neighboring cells (see the board).
Board after step 2 3. Step: place pup (row 3, column 7)
After crosses, the mint region has only one legal cell — row 3, column 7. Place a pup there. Mark crosses along the row, column, and neighboring cells (see the board).
Board after step 3 4. Step: place pup (row 1, column 1)
After crosses, the cyan region has only one legal cell — row 1, column 1. Place a pup there. Mark crosses along the row, column, and neighboring cells (see the board).
Board after step 4 5. Step: place pup (row 9, column 4)
After crosses, the coral region has only one legal cell — row 9, column 4. Place a pup there. Mark crosses along the row, column, and neighboring cells (see the board).
Board after step 5 6. Step: mark X in column 2
The green region is confined to column 2. Mark illegal cells with X.
Board after step 6 7. Step: mark X in column 2
The green region is confined to column 2. Mark illegal cells with X.
Board after step 7 8. Step: mark X in column 2
The green region is confined to column 2. Mark illegal cells with X.
Board after step 8 9. Step: mark X in column 3
The yellow region is confined to column 3. Mark illegal cells with X.
Board after step 9 10. 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 10 11. 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 11 12. 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 12 13. 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 13 14. Step: place pup (row 7, column 2)
After previous pups, column 2 has only one free cell — row 7. Place the green region's pup here. Mark crosses along the row, column, and neighboring cells (see the board).
Board after step 14 15. 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 15 16. 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 16 17. 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 17 18. 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 18 19. Step: place pup (row 5, column 5)
After previous pups, row 5 has only one free cell — column 5. Place the orange region's pup here. Mark crosses along the row, column, and neighboring cells (see the board).
Board after step 19 20. Step: place pup (row 6, column 8)
After previous pups, row 6 has only one free cell — column 8. Place the lavender region's pup here. Mark crosses along the row, column, and neighboring cells (see the board).
Board after step 20 21. Step: place pup (row 8, column 6)
After previous pups, column 6 has only one free cell — row 8. Place the blue region's pup here. Mark crosses along the row, column, and neighboring cells (see the board).
Board after step 21
Final solution
All pups placed correctly: R1 C1, R2 C9, R3 C7, R4 C3, R5 C5, R6 C8, R7 C2, R8 C6, R9 C4, R10 C10
Similar difficulty levels
FAQ
- How do I solve Bulldoku level 840?
- Follow the 21 steps above: find forced placements first, then mark impossible cells with X.
- Where can I play level 840 online?
- Click "Play Level 840" to open the free browser game with this exact board.