Sudoku-8-X Thumbnail of a Sudoku-8-X puzzle.

Size:
8x8.
Elements:
1, 2, 3, 4, 5, 6, 7, and 8.
Groups: Twenty-six total.
The 8 rows.
The 8 columns.
The 8 4x2 rectangles.
The 2 diagonals.
Instructions:
Precise details on group numbering.
Answer grids:

Puzzle Difficulty levels and Examples

Difficulty LevelLowHighExample
Easiest 2 2 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid
Easy 3 4 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid
Medium 5 8 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid
Difficult 9 12 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid
Challenging 13 16