Sudoku Solver Paper

Links

• Sudoku solver – Now if I could only stop making mistakes
• Import to solver here.
• Sudoku Solver #2
• Pencil & Paper Sudoku algorithm
• Neuer – Fund über Sudoku-Geometrie – corner 2×2 boxes have the same numbers in them as the ring around the center square

 

Notes

• Be flexible: There appears to be a tendency to focus on a subset of techniques using only rows.   Use the solver to work through some examples.  Observe casually the techniques used and note which ones you have been skipping or not using enough.  
• Use your eyes to find probabilistic soft entry spots.  For example well populated row that passes through a well populated square.
• Using the solver paper makes more work.  It is useful to observe patterns but gets in the way too.

 

Solve your sudoku using this paper.  Circle the given square number.  X out the eliminated values of the square.  The following jpg image is sized to print out on 8.5 x 11 paper

Blank=

0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0

 

 Easy Example for study 

0,1,0,0,0,0,0,3,0,3,0,0,6,0,0,9,0,0,2,0,0,9,0,8,0,0,4,0,8,0,4,6,0,0,0,0,0,5,7,0,0,0,1,8,0,0,0,0,0,8,1,0,4,0,7,0,0,3,0,4,0,,0,1,0,0,2,0,0,6,0,0,9,0,4,0,0,0,0,0,6,0

 

Medium Example for study

0,1,0,4,0,2,0,0,0,0,0,2,0,5,0,0,0,7,0,0,0,3,0,6,2,8,0,0,0,3,0,0,0,1,0,2,0,7,0,0,0,0,0,5,0,4,0,8,0,0,0,6,0,0,0,6,0,8,0,7,0,2,0,5,0,0,0,2,0,4,0,00,0,0,5,0,1,0,3,0

 

Hard Example: Does not require the X or Y wing strategy

0,0,0,4,3,6,0,1,0,0,9,0,0,0,0,0,0,7,0,0,2,0,0,0,0,0,0,0,5,0,8,0,0,0,0,4,0,0,0,0,0,0,0,0,0,1,0,0,0,0,2,0,3,0,0,0,0,0,0,0,2,0,0,3,0,0,0,0,0,0,6,0,0,4,0,9,7,5,0,0,0

 

Tough – Requires X and Y wing

309000400200709000087000000750060230600904008028050041000000590000106007006000104

Sudoku from Plane to El Paso – Easy:  Use the sudoku solver step by step to increase your quick solution recognition

0,0,0,0,0,0,0,0,0,0,2,1,4,0,5,0,0,0,8,9,0,0,0,1,0,0,5,0,0,5,0,7,0,0,1,0,0,0,0,0,0,0,0,9,0,6,7,4,3,0,0,0,0,0,0,0,0,0,0,4,1,0,2,0,0,0,2,0,0,7,8,0,0,0,0,0,0,8,0,4,0

 

Sudoku Solution –Solution steps from sudokuwiki.com solver.  
Solution: 546987231721435869893621475935872614182546397674319528368794152419253786257168943
Clues: 24
Final Score: 98
Grade: Moderate
 

Note the strategies are broken out for you. 

---

Step 1

• 1 is the only possible number in A9
• 9 is the only possible number in D1
• 4 is the only possible number in E5
• 7 is the only possible number in E9

Step 2

• Last candidate, 8, in F9 changed to solution

Step 3 – Hidden Singles  docs

• 1 found once at F5 in row, 3 candidate removed
• 4 found once at C7 in row, 3 candidate removed
• 4 found once at D9 in column, 2 candidate removed
• 5 found once at E4 in box, 3 candidate removed
• 7 found once at A6 in column, 4 candidate removed
• 8 found once at D4 in box, 1 candidate removed
• 9 found once at F6 in row/box, 1 candidate removed
• Last candidate, 7, in A6 changed to solution
• Last candidate, 4, in C7 changed to solution
• Last candidate, 8, in D4 changed to solution
• Last candidate, 4, in D9 changed to solution
• Last candidate, 5, in E4 changed to solution
• Last candidate, 1, in F5 changed to solution
• Last candidate, 9, in F6 changed to solution

Step 4

• 1 is the only possible number in J4

Step 5

• 7 is the only possible number in G4

Step 6

• Last candidate, 6, in C4 changed to solution
• Last candidate, 3, in D2 changed to solution

Step 7

• 3 is the only possible number in E7

Step 8

• 6 is the only possible number in D7

Step 9

• 6 is the only possible number in E6

Step 10

• 2 is the only possible number in D6

Step 11

• Last candidate, 9, in A4 changed to solution
• Last candidate, 3, in H6 changed to solution

Step 12 – Naked Pair  docs

• Naked Pair 3/7 in Box 1, on cells [B1,C3]
  – removes 3 from A1
  – removes 3 from A3
• Naked Pair 6/9 in Row H, on cells [H3,H9]
  – removes 6 from H2
  – removes 6/9 from H5
•  
• Last candidate, 6, in A3 changed to solution
• Last candidate, 5, in H5 changed to solution

Step 13

• Last candidate, 9, in H3 changed to solution

Step 14

• Last candidate, 6, in H9 changed to solution

Step 15

• 6 is the only possible number in B8

Step 16

• 7 is the only possible number in C8

Step 17

• 7 is the only possible number in B1
• 7 is the only possible number in J3

Step 18

• 2 is the only possible number in J1

Step 19

• 2 is the only possible number in E3

Step 20

• 8 is the only possible number in E2
• 8 is the only possible number in G3

Step 21

• 1 is the only possible number in E1
• 3 is the only possible number in G1
• 1 is the only possible number in H2
• 3 is the only possible number in J9

Step 22

• 3 is the only possible number in C3
• 3 is the only possible number in A8
• 4 is the only possible number in H1
• 9 is the only possible number in J7

Step 23

• 4 is the only possible number in A2
• 3 is the only possible number in B5
• 2 is the only possible number in A7
• 9 is the only possible number in B9
• 2 is the only possible number in F8
• 9 is the only possible number in G5
• 5 is the only possible number in G8

Step 24

• 5 is the only possible number in A1
• 8 is the only possible number in A5
• 2 is the only possible number in C5
• 8 is the only possible number in B7
• 5 is the only possible number in F7
• 5 is the only possible number in J2
• 6 is the only possible number in J5

Step 25

• 6 is the only possible number in G2

​

Sudoku Technique Leveling – Puzzles according to level of techniques required. In order of increasing difficulty

• Row / Column / Square is the highest technique required
• Row / Column / Square is the highest technique required #2
• Naked Triple – Significantly harder to recognize the solution visually  
• Critical row pointing pair of 2s and a  naked triple in the center column