Sudoku diagonal
In the diagram, digits in one of the diagonals can’t be repeated.

Sudoku X
Digits can’t be repeated in both diagonals.

HyperSudoku
In the diagram 9x9, you can find additional 3x3 four boxes, where digits also can’t be repeated.
Specific method for this kind of Sudoku is about finding digits, which can be put in both overlapping boxes at the same time.

Double Sudoku
Sudoku which consists of two sudoku diagrams.

Tripple Sudoku
Sudoku which consists of three sudoku diagrams.

Double column Sudoku
Sudoku which consists of two sudoku diagrams stacked in one column.

Tripple column Sudoku
Sudoku which consists of three sudoku diagrams stacked in one column.