Logic Masters Deutschland e.V.

Normal sudoku rules apply.

There are nine "negative digits" in the puzzle whose value is counted as the negative of the digit in the square for the purposes of the killer cage sums. There is one negative digit per row, column and 3x3 box, and each of the numbers 1-9 is a negative digit somewhere. Part of the solve is identifying which cells are negative.

Values in a killer cage must sum to the number indicated in the top-left. Note: the two eight-cell cages have sum ZERO (this is hard to see on F-puzzles/CtC app). Digits may not repeat in cages. This includes not allowing a negative and positive of the same digit in one cage.

The green lines are German Whispers: consecutive digits (not values so ignore negatives) on green lines must differ by at least five. Digits may repeat on German Whispers if allowed by other rules.

Cells with grey squares are even (can be negative).

CtC App: Link

F-puzzles: Link

Note: I think the break-in is incredibly beautiful despite being very tricky. The good news is that the puzzle is quite easy after the first (considerably intricate) piece of logic.