1)   Royal Sudoku 1.0 A complicated version of sudoku game destined for real kings of puzzles. Rules are simple. Each row, column and subgrid inibox (4x4) comprises the numbers 1 through 16 or letters A through P or anything else. 2)   Sudoku16 1.0 Sudoku16 is complicated version of sudoku game destined for real puzzle lovers. Rules are simple. Each row, column and subgrid inibox (4x4) comprises the numbers 1 through 16 or letters A through P or anything else. 3)   Elite Sudoku 1.0 The most popular logic puzzle in Japan. The rules are simple. Each row, column and minibox comprises the numbers 1 through 9. The solver must complete the missing numbers. Sudoku is recommended by some teachers as an exercise in logical reasoning. 4)   Good Old Sudoku 1.0 The most popular logic puzzle in Japan. The rules are simple. Each row, column and minibox comprises the numbers 1 through 9. The solver must complete the missing numbers. Sudoku is recommended by some teachers as an exercise in logical reasoning.