Challenging Sudoku Eight Logic Puzzles (Vol 1) Step-by-Step Instructions for Puzzle 147   (45/64) Diff: 14/4A.2133.222B.3595 Printable puzzle or puzzle with instructions The numbers in the puzzle below refer to the step number at which the value of the location can be deduced. Locations without step numbers contain the initial values found in corresponding puzzle in your edition of the book.

Rows are numbered top to bottom, columns from left to right, and rectangles from left to right and then top to bottom. Coordinates are (col, row). Precise details on numbering within each group are specified in the on-line instructions for 'HyperSudoku-8up' puzzles.

Step 1. There are 4 independent moves.

• The only spot left for 6 in the 6th row is at (2, 6).
• The only spot left for 3 in the 7th 2x4 rectangle is at (6, 6).
• The only spot left for 5 in the 2nd 4x2 inner rectangle is at (5, 7).
• The only spot left for 2 in the 2nd 4x2 inner rectangle is at (7, 6).

Step 2. There is 1 independent move.

• 1 must be placed at (3, 1) because it is the only value left that is not already in the 1st row, the 3rd column or the 2nd 2x4 rectangle.

Step 3. There are 2 independent moves.

• The only spot left for 1 in the 4th row is at (2, 4).
• The only spot left for 1 in the 3rd 2x4 rectangle is at (5, 3).

Step 4. There is 1 independent move.

• The only spot left for 2 in the 3rd 2x4 rectangle is at (5, 2).

Step 5. There are 3 independent moves.

• The only spot left for 2 in the 3rd row is at (8, 3).
• The only spot left for 2 in the 1st 2x4 rectangle is at (1, 4).
• The only spot left for 6 in the 1st 4x2 inner rectangle is at (4, 2).

Step 6. There are 3 independent moves.

• The only spot left for 3 in the 2nd row is at (7, 2).
• The only spot left for 8 in the 3rd row is at (7, 3).
• The only spot left for 7 in the 1st 2x4 rectangle is at (1, 1).

Step 7. There are 2 independent moves.

• The only spot left for 5 in the 1st row is at (8, 1).
• The only spot left for 7 in the 3rd row is at (6, 3).

Step 8. There are 2 independent moves.

• The only spot left for 6 in the 1st row is at (5, 1).
• The only spot left for 6 in the 4th 2x4 rectangle is at (8, 4).

Step 9. There are 2 independent moves.

• The only spot left for 7 in the 4th 2x4 rectangle is at (7, 4).
• The only spot left for 6 in the 7th 2x4 rectangle is at (6, 8).

Step 10. There are 2 independent moves.

• 2 must be placed at (3, 8) because it is the only value left that is not already in the 8th row, the 3rd column or the 6th 2x4 rectangle.
• 3 must be placed at (1, 7) because it is the only value left that is not already in the 7th row, the 1st column or the 5th 2x4 rectangle.

Step 11. There are 3 independent moves.

• The only spot left for 3 in the 3rd column is at (3, 3).
• The only spot left for 2 in the 5th 2x4 rectangle is at (2, 7).
• The only spot left for 3 in the 6th 2x4 rectangle is at (4, 5).

Step 12. There are 5 independent moves.

• The only spot left for 1 in the 5th row is at (7, 5).
• The only spot left for 7 in the 7th row is at (4, 7).
• The only spot left for 4 in the 2nd 2x4 rectangle is at (3, 4).
• The only spot left for 1 in the 6th 2x4 rectangle is at (4, 8).
• The only spot left for 4 in the 1st 4x2 inner rectangle is at (2, 3).

Step 13. There are 10 independent moves.

• The only spot left for 7 in the 6th row is at (8, 6).
• The only spot left for 4 in the 8th row is at (5, 8).
• The only spot left for 5 in the 1st 2x4 rectangle is at (1, 2).
• The only spot left for 8 in the 2nd 2x4 rectangle is at (4, 4).
• The only spot left for 4 in the 3rd 2x4 rectangle is at (6, 2).
• The only spot left for 4 in the 5th 2x4 rectangle is at (1, 5).
• The only spot left for 8 in the 6th 2x4 rectangle is at (3, 7).
• The only spot left for 5 in the 8th 2x4 rectangle is at (7, 8).
• The only spot left for 5 in the 1st 4x2 inner rectangle is at (4, 3).
• The only spot left for 8 in the 2nd 4x2 inner rectangle is at (5, 6).

Step 14. There are 5 independent moves.

• The only spot left for 7 in the 8th row is at (2, 8).
• The only spot left for 5 in the 3rd 2x4 rectangle is at (6, 4).
• The only spot left for 5 in the 5th 2x4 rectangle is at (2, 5).
• The only spot left for 7 in the 7th 2x4 rectangle is at (5, 5).
• The only spot left for 8 in the 8th 2x4 rectangle is at (8, 5).