Logic Masters Deutschland e.V.

When I created Skyscraper Sums Sandwiches a while ago, it occurred to me that I hadn't yet mixed my favorite two variants together, so here you go:

The Rules:

1. [Sudoku] Normal sudoku rules apply - fill every row, column, and 3x3 box with the digits from 1 to 9 once each.
2. Clues outside the grid are simultaneously sandwich clues, and x-sum clues (i.e. if the sandwich clue is 13, then the x-sum clue must also be 13) A single question mark must be a one digit number and a double question mark must be two digit number (no leading zeros).
   • [Sandwich]: The sum of the digits between the 1 and the 9 in that row or column.
   • [X-Sums:] The sum of the the first x cells in that row from the direction of the clue where x is the digit in the cell next to the clue.

The Puzzle:

Four solving options for you:

• Copy down this picture onto paper (that's my favorite!) or print.
  
• Simple Sudokupad Link:
• Sudokupad Link with room for outside clues. The answer check requires no large numbers around the outside.
• Sudokupad Link with Fog - for guided solve path - you'll have to pretend you haven't seen the grid.