Variations on Advanced Sudoku Logic Puzzles (Vol 1) Step-by-Step Instructions for Puzzle 177   (146/256) Diff: 10/99.9999.9995 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-16' puzzles.

Step 1. There are 22 independent moves.

• The only spot left for 8 in the 5th row is at (9, 5).
• The only spot left for E in the 16th row is at (16, 16).
• The only spot left for 1 in the 11th column is at (11, 7).
• The only spot left for 9 in the 13th column is at (13, 11).
• The only spot left for A in the 4th 4x4 square is at (16, 4).
• The only spot left for 3 in the 4th 4x4 square is at (13, 2).
• The only spot left for 1 in the 6th 4x4 square is at (6, 8).
• The only spot left for F in the 7th 4x4 square is at (12, 8).
• The only spot left for 7 in the 7th 4x4 square is at (9, 6).
• The only spot left for 8 in the 8th 4x4 square is at (14, 8).
• The only spot left for 8 in the 9th 4x4 square is at (1, 9).
• The only spot left for 5 in the 11th 4x4 square is at (10, 12).
• The only spot left for C in the 11th 4x4 square is at (9, 11).
• The only spot left for 2 in the 11th 4x4 square is at (11, 9).
• The only spot left for 1 in the 12th 4x4 square is at (13, 10).
• The only spot left for B in the 12th 4x4 square is at (16, 9).
• The only spot left for 4 in the 1st 4x4 inner square is at (3, 5).
• The only spot left for 7 in the 1st 4x4 inner square is at (5, 4).
• The only spot left for 2 in the 2nd 4x4 inner square is at (13, 6).
• The only spot left for C in the 2nd 4x4 inner square is at (12, 3).
• The only spot left for 1 in the 4th 4x4 inner square is at (12, 13).
• The only spot left for D in the 4th 4x4 inner square is at (11, 11).

Step 2. There are 15 independent moves.

• The only spot left for 8 in the 2nd row is at (8, 2).
• The only spot left for E in the 5th row is at (1, 5).
• The only spot left for 4 in the 8th row is at (16, 8).
• The only spot left for 5 in the 13th column is at (13, 16).
• The only spot left for 1 in the 3rd 4x4 square is at (10, 1).
• The only spot left for 8 in the 4th 4x4 square is at (15, 1).
• The only spot left for 4 in the 7th 4x4 square is at (12, 7).
• The only spot left for 9 in the 11th 4x4 square is at (10, 9).
• The only spot left for E in the 12th 4x4 square is at (15, 9).
• The only spot left for 1 in the 13th 4x4 square is at (1, 15).
• The only spot left for 3 in the 2nd 4x4 inner square is at (11, 6).
• The only spot left for 6 in the 2nd 4x4 inner square is at (14, 5).
• The only spot left for 4 in the 2nd 4x4 inner square is at (11, 4).
• The only spot left for 4 in the 3rd 4x4 inner square is at (6, 13).
• The only spot left for 8 in the 4th 4x4 inner square is at (13, 13).

Step 3. There are 13 independent moves.

• The only spot left for D in the 5th row is at (2, 5).
• The only spot left for 6 in the 6th row is at (3, 6).
• The only spot left for F in the 13th row is at (3, 13).
• The only spot left for C in the 8th column is at (8, 8).
• The only spot left for 5 in the 11th column is at (11, 5).
• The only spot left for 6 in the 16th column is at (16, 3).
• The only spot left for 4 in the 4th 4x4 square is at (15, 3).
• The only spot left for 3 in the 8th 4x4 square is at (16, 7).
• The only spot left for 8 in the 14th 4x4 square is at (7, 16).
• The only spot left for 5 in the 15th 4x4 square is at (9, 15).
• The only spot left for 8 in the 15th 4x4 square is at (10, 14).
• The only spot left for 6 in the 16th 4x4 square is at (15, 13).
• The only spot left for A in the 2nd 4x4 inner square is at (12, 5).

Step 4. There are 14 independent moves.

• The only spot left for 0 in the 5th row is at (7, 5).
• The only spot left for F in the 9th row is at (8, 9).
• The only spot left for 7 in the 13th row is at (10, 13).
• The only spot left for 0 in the 13th row is at (1, 13).
• The only spot left for 4 in the 15th row is at (14, 15).
• The only spot left for A in the 3rd column is at (3, 9).
• The only spot left for 9 in the 16th column is at (16, 15).
• The only spot left for 0 in the 16th column is at (16, 12).
• The only spot left for 9 in the 4th 4x4 square is at (14, 1).
• The only spot left for 0 in the 8th 4x4 square is at (14, 7).
• The only spot left for 5 in the 8th 4x4 square is at (16, 6).
• The only spot left for F in the 9th 4x4 square is at (2, 12).
• The only spot left for E in the 15th 4x4 square is at (10, 15).
• The only spot left for A in the 15th 4x4 square is at (9, 13).

Step 5. There are 11 independent moves.

• The only spot left for C in the 1st row is at (5, 1).
• The only spot left for 3 in the 9th row is at (4, 9).
• The only spot left for 9 in the 4th column is at (4, 8).
• The only spot left for A in the 14th column is at (14, 10).
• The only spot left for 9 in the 1st 4x4 square is at (1, 4).
• The only spot left for C in the 4th 4x4 square is at (14, 2).
• The only spot left for 0 in the 7th 4x4 square is at (10, 8).
• The only spot left for E in the 7th 4x4 square is at (9, 7).
• The only spot left for 0 in the 3rd 4x4 inner square is at (5, 14).
• The only spot left for A in the 3rd 4x4 inner square is at (5, 12).
• The only spot left for 0 in the 4th 4x4 inner square is at (12, 11).

Step 6. There are 23 independent moves.

• The only spot left for 6 in the 4th row is at (9, 4).
• The only spot left for 5 in the 8th row is at (7, 8).
• The only spot left for D in the 8th row is at (5, 8).
• The only spot left for 7 in the 9th row is at (12, 9).
• The only spot left for F in the 5th column is at (5, 6).
• The only spot left for 9 in the 5th column is at (5, 3).
• The only spot left for B in the 5th column is at (5, 2).
• The only spot left for 2 in the 14th column is at (14, 16).
• The only spot left for 6 in the 1st 4x4 square is at (2, 2).
• The only spot left for 0 in the 2nd 4x4 square is at (8, 3).
• The only spot left for F in the 2nd 4x4 square is at (7, 1).
• The only spot left for 3 in the 5th 4x4 square is at (2, 8).
• The only spot left for 5 in the 5th 4x4 square is at (1, 7).
• The only spot left for D in the 7th 4x4 square is at (10, 7).
• The only spot left for 0 in the 9th 4x4 square is at (2, 10).
• The only spot left for 9 in the 10th 4x4 square is at (7, 12).
• The only spot left for B in the 11th 4x4 square is at (12, 10).
• The only spot left for 2 in the 12th 4x4 square is at (15, 12).
• The only spot left for A in the 1st 4x4 inner square is at (6, 6).
• The only spot left for 9 in the 3rd 4x4 inner square is at (6, 14).
• The only spot left for D in the 3rd 4x4 inner square is at (4, 12).
• The only spot left for B in the 4th 4x4 inner square is at (11, 14).
• The only spot left for 6 in the 4th 4x4 inner square is at (12, 12).

Step 7. There are 16 independent moves.

• The only spot left for B in the 7th column is at (7, 11).
• The only spot left for D in the 8th column is at (8, 10).
• The only spot left for 7 in the 15th column is at (15, 15).
• The only spot left for B in the 1st 4x4 square is at (2, 1).
• The only spot left for D in the 1st 4x4 square is at (1, 1).
• The only spot left for 2 in the 5th 4x4 square is at (2, 7).
• The only spot left for 9 in the 6th 4x4 square is at (8, 7).
• The only spot left for A in the 8th 4x4 square is at (15, 7).
• The only spot left for D in the 8th 4x4 square is at (15, 6).
• The only spot left for 7 in the 12th 4x4 square is at (14, 12).
• The only spot left for 2 in the 13th 4x4 square is at (4, 15).
• The only spot left for B in the 14th 4x4 square is at (8, 16).
• The only spot left for F in the 14th 4x4 square is at (6, 15).
• The only spot left for F in the 15th 4x4 square is at (11, 16).
• The only spot left for 0 in the 2nd 4x4 inner square is at (13, 4).
• The only spot left for F in the 4th 4x4 inner square is at (14, 14).

Step 8. There are 14 independent moves.

• The only spot left for D in the 4th row is at (6, 4).
• The only spot left for 2 in the 11th row is at (1, 11).
• The only spot left for 3 in the 1st column is at (1, 14).
• The only spot left for 7 in the 7th column is at (7, 10).
• The only spot left for 6 in the 8th column is at (8, 11).
• The only spot left for 3 in the 1st 4x4 square is at (3, 1).
• The only spot left for D in the 3rd 4x4 square is at (9, 2).
• The only spot left for 6 in the 6th 4x4 square is at (7, 7).
• The only spot left for 3 in the 10th 4x4 square is at (6, 11).
• The only spot left for A in the 13th 4x4 square is at (4, 16).
• The only spot left for A in the 14th 4x4 square is at (8, 15).
• The only spot left for 3 in the 14th 4x4 square is at (7, 15).
• The only spot left for 7 in the 14th 4x4 square is at (8, 14).
• The only spot left for D in the 2nd 4x4 inner square is at (13, 3).

Step 9. There are 13 independent moves.

• The only spot left for E in the 1st row is at (12, 1).
• The only spot left for 4 in the 1st column is at (1, 16).
• The only spot left for 2 in the 7th column is at (7, 4).
• The only spot left for 0 in the 1st 4x4 square is at (3, 2).
• The only spot left for E in the 2nd 4x4 square is at (6, 2).
• The only spot left for 0 in the 3rd 4x4 square is at (9, 1).
• The only spot left for 4 in the 9th 4x4 square is at (2, 11).
• The only spot left for 6 in the 9th 4x4 square is at (1, 10).
• The only spot left for 2 in the 10th 4x4 square is at (6, 10).
• The only spot left for 7 in the 13th 4x4 square is at (2, 16).
• The only spot left for E in the 1st 4x4 inner square is at (3, 4).
• The only spot left for 6 in the 3rd 4x4 inner square is at (4, 14).
• The only spot left for 7 in the 3rd 4x4 inner square is at (4, 11).

Step 10. There are 5 independent moves.

• The only spot left for 5 in the 4th column is at (4, 1).
• The only spot left for 5 in the 2nd 4x4 square is at (6, 3).
• The only spot left for 5 in the 3rd 4x4 square is at (12, 2).
• The only spot left for 2 in the 1st 4x4 inner square is at (3, 3).
• The only spot left for 5 in the 3rd 4x4 inner square is at (3, 14).