Logic Masters Deutschland e.V.

This is my submission to this weeks setting challenge by Scojo which is about X-Sums and nabner lines. I decided to go for a loop puzzle with variations of both rules (Internal X-Sums and Run-on-Nabner). Thanks Flinty for testing and feedback.

• Normal sudoku rules apply.
• Loop: Draw a one cell wide loop through the centers of some cells. The loop can't touch itself, not even diagonally.
• Run-on-Nabner: Digits that are 1, 2 or 3 steps apart on the loop differ by 2 or more. For example, if there is a 4 on the loop, the 6 surrounding cells on the loop (the next 3 and the previous 3) can't include 3, 4 or 5.
• Internal X-Sums: A digit N in a cell containing a number X in its top left corner is on the loop and indicates that that cell sees N loop cells in the row and column combined including itself, and that those digits sum to X. Non-loop cells block vision.
• Kropki Pairs: Digits joined by a white dot are consecutive. Not all dots are given.

Click on the puzzle image to play!

Example

This example shows how a part of the loop could look like. Cells with a number in the top-left "see" an amount of loop cells equal to their digit and the seen loop cells (which can include repeats) sum to the number indicated. Every 4 cell sequence along the loop acts as a 4 cell nabner line. The 5 in the top row eliminates 4, 5 and 6 from the 6 surrounding cells (which are 927-913).

Solve Video

Click here to watch Frank puzzle live solving this puzzle on YouTube.