Logic Masters Deutschland e.V.

• Normal sudoku rules apply.
• There is a path (not a loop) in the grid that travels horizontally and vertically and visits every cell in the grid exactly once. In cells where the path starts or turns, the digit in the cell indicates how many steps the path travels straight before turning again.
• The path starts and ends somewhere in the top left 3x3 box.
• The grid is toroidal with respect to the path, eg the path can wrap from r1c1 to r1c9 or r9c1.
• Clues in the corner of a cell are 'Path Killer' clues, and are the sum of the digits on the straight section of the path that passes through that cell, including the start/turn cells at the ends.
• Sections of the path containing a clue do NOT wrap at all, ie it must turn at both ends without leaving the grid.
• The path cannot turn on a clue.

You may want to first try the original Grand Tour Sudoku which is somewhat easier, and the path cannot wrap around.

Penpa link

Example of the Path Killer clues

The hints below give a walkthrough of the solve path. Select to view

1. Since the path cannot turn on a clue, all the clues in column 4 must have paths going horizontally.
2. Considering the clues in row 2, can the 30 clue be horizontal?
3. Can the 14 be vertical? How would that impact the 30?
4. Consider the total for row 6. You can determine the step number for both clues, though not the direction yet.
5. Can the right end of the 31 turn down? It would have to join the 35.
6. Can the 18 be horizontal? Can the 1 be in either the 31 or the 18?
7. Look at all the options for the length of the 18. Only one is valid. You can complete the 18 and extend the path.
8. Remember that the start and end are in box 1, so the right end of the 31 must turn and escape. What is the minimum size of the turn at the other end?
9. Can the 2 ends now in column 9 connect? What would the 30 have to do? Connecting the bottom of the 30 gives a digit.
10. Given the new constraint, consider the minimum size of the 28 in row 1. You can get the other end.
11. Don't get stuck in box 1. Look at where the left end of the 35 can connect to.
12. The 29 in row 2 is now forced, but can the path start on it? How big can the 18 in row 3 be?
13. The directionality of the various ends will help you complete the rest of the path.
14. Make sure you have entered all the digits on turns, then do all the sudoku you can.
15. Use the path killer clues to eliminate candidates. It's easiest to start with the clues at the top, and work down, doing as much sudoku as you can along the way. Look carefully at the maximum, then minimum candidates in the 30.