Sudoku-X-d2 Thumbnail of a Sudoku-X-d2 puzzle.

Size:
9x9.
Elements:
1, 2, 3, 4, 5, 6, 7, 8, and 9.
Groups: Twenty-nine total.
The 9 rows.
The 9 columns.
The 9 3x3 squares.
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 14 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid
Challenging 15 20
Tournament 21 29