Links
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