A sudoku variants book with Frame Sudoku puzzles: a hybrid between Outside Sudoku and Killer sudoku and a little bit of Kakuro, too
The rules are simple: the clues outside the grid give you the sum of the three nearest numbers. It is up to you to fill in all 81 squares All other Sudoku rules apply.
But wait In addition to classic (aka "vanilla" flavor) Frame Sudoku, there are 5 more flavors in the same Frame Sudoku format: Odd-Even Frame Sudoku Frame Diagonal Sudoku Frame Consecutive Sudoku Frame Non-Consecutive Sudoku Frame Jigsaw Sudoku The puzzles are rated for difficulty on a standard EASY-COOL-THINKER-BRAIN-IQ scale.
Ready?