- Gattai is a Japanese word meaning merged or fused; this term is used for overlapping sudoku. A number after the word "Gattai" indicates how many 9 x 9 sudokus are in the puzzle .

- Gattai is a Japanese word meaning merged or fused; this term is used for overlapping sudoku. A number after the word "Gattai" indicates how many 9 x 9 sudokus are in the puzzle .

- Flower Sudoku has five sudoku puzzles in layout, similar to Samurai Sudoku. However, these puzzles overlap each other much more than in Samurai. The center grid is fully covered by the remaining four sub-puzzles.

- Flower Sudoku has five sudoku puzzles in layout, similar to Samurai Sudoku. However, these puzzles overlap each other much more than in Samurai. The center grid is fully covered by the remaining four sub-puzzles.

- Triple Doku consists of three grids 9 x 9. The numbers must be placed correctly for all puzzle squares.

- Triple Doku consists of three grids 9 x 9. The numbers must be placed correctly for all puzzle squares.

- W Sudoku is made up with five grids and formed W word.It is means that numbers are put in all five grids exactly.

- W Sudoku is made up with five grids and formed W word.It is means that numbers are put in all five grids exactly.

- Flower Sudoku has five sudoku puzzles in layout, similar to Samurai Sudoku. However, these puzzles overlap each other much more than in Samurai. The center grid is fully covered by the remaining four sub-puzzles.

- Twodoku consists of two grids 9 x 9. The numbers must be placed correctly for both puzzle squares.

- Twodoku consists of two grids 9 x 9. The numbers must be placed correctly for both puzzle squares.

- Clueless Sudoku is made up with nine nonoverlap 9*9 Sudokus.The 10th 9*9 Sudoku is hidden in the topic and marked with dark gray grids.

- Clueless Sudoku is made up with nine nonoverlap 9*9 Sudokus.The 10th 9*9 Sudoku is hidden in the topic and marked with dark gray grids.

- Cross Sudoku has five merged grids. The numbers must be placed correctly for all the five puzzle squares.

- Cross Sudoku has five merged grids. The numbers must be placed correctly for all the five puzzle squares.

- Named for the warrior monks of medieval Japan, Sohei Sudoku has four merged grids. Each grid has two overlapping areas.

- Named for the warrior monks of medieval Japan, Sohei Sudoku has four merged grids. Each grid has two overlapping areas.

- Samurai Sudoku ("Gattai-5") is one of the sudoku variation with overlapping sudoku grids. The puzzle consists of five grids, one in the center and the other 4 overlapping each corner grid of the central one. 5 normal 9x9 Sudoku diagrams are interweaved in a way so that no single diagram can be solved alone, but all 5 diagrams together have a unique solution.

- Samurai Sudoku ("Gattai-5") is one of the sudoku variation with overlapping sudoku grids. The puzzle consists of five grids, one in the center and the other 4 overlapping each corner grid of the central one. 5 normal 9x9 Sudoku diagrams are interweaved in a way so that no single diagram can be solved alone, but all 5 diagrams together have a unique solution.

- W Sudoku is made up with five grids and formed W word.It is means that numbers are put in all five grids exactly.

- Clueless Sudoku is made up with nine nonoverlap 9*9 Sudokus.The 10th 9*9 Sudoku is hidden in the topic and marked with dark gray grids.

- Cross Sudoku has five merged grids. The numbers must be placed correctly for all the five puzzle squares.

- Twin Corresponding Sudoku consists of a pair of standard sudoku puzzles each with some starting digits. To get a complete solution for the twin puzzles, it is necessary to solve each twin puzzle, but the complete solution of the twin puzzles will be obtained by substituting the corresponding values of the digits from one twin sudoku into the other.

- Twin Corresponding Sudoku consists of a pair of standard sudoku puzzles each with some starting digits. To get a complete solution for the twin puzzles, it is necessary to solve each twin puzzle, but the complete solution of the twin puzzles will be obtained by substituting the corresponding values of the digits from one twin sudoku into the other.