Consecutive Sudoku - 200 Hard Puzzles Vol.3 - David Smith - Bog

A Consecutive Sudoku puzzle adds one extra constraint to the standard Sudoku grid - not only must you place 1 to 9 (or 1 to whatever the width of the puzzle is) in each row, column and bold-lined box, but also obey the white consecutive markers: White bars between squares indicate that the squares are consecutive - meaning that the numbers in these two squares have a numerical difference of '1'. For example: 1 and 2; or 4 and 5. If there is no white bar then the numbers are not consecutive.