Logic Masters Deutschland e.V.

Rules

• Divide the grid into two orthogonally connected regions. One region is a Castle Wall (Delta), the other is an A38 (Crossing).


• Castle Wall (Delta):
  • Draw a directed loop that travels orthogonally through the centers of some empty cells in the Castle Wall region.
  • This loop may not enter the A38 region.
  • This loop may not cross itself or overlap.
  • All squared clues must be in the Castle Wall region, and they cannot be visited by this loop.
  • White squares must be inside this loop. Black squares must be outside this loop. Grey squares may be inside or outside this loop.
  • A number in a squared clue indicates the amount of steps made towards that cell minus the amount of steps made away from the cell, when completing a single round trip of this loop.
  • Region borders block vision. In other words, a squared clue sees all steps up to the first region border (or the edge of the grid) in every cardinal direction (north, east, west, south) from that cell's standpoint.


• A38 (Crossing):
  • Draw a directed loop that travels orthogonally through the centers of ALL empty cells in the A38 region.
  • This loop may not enter the Castle Wall region.
  • This loop may cross itself, but may not turn at an intersection or otherwise overlap.
  • The cell with the black circle must be in the A38 region, and is considered the starting point of this loop.
  • All non-squared clues must be in the A38 region, and they cannot be visited by this loop.
  • A number clue N indicates that the Nth instance of a cell being visited by this loop in the (up to) eight cells surrounding that clue is a pass cell. Note that crosses are visited twice.
  • There are no superfluous clues, that is, every such N must correspond to a pass cell.
  • A question mark may represent any strictly positive integer, as long as numbers don't repeat in the clue. For example, a "7/?" clue could represent "7/3" or "7/10", but not "7/7".
  • Every pass cell is indicated by at least one clue and every clue indicates all pass cells touching it. This loop may not cross itself on a pass cell.
  • This loop must then alternate between pass cells and crosses, starting with a pass cell from the black circle onwards and ending with a cross before returning to the black circle.

Example Puzzle (10x10)

• SudokuPad
• Penpa+

Main Puzzle (17x20)

• SudokuPad
• Penpa+