Logic Masters Deutschland e.V.

This puzzle is a hybrid between an obscure Pencil Puzzle genre Cogs and Sudoku.

Rules:

• Normal 9x9 Sudoku rules apply: Place the digits 1-9 exactly once in every row, column, and 3x3 box.
• Arrows: There are circles in the grid with attached arrows. The digit in the circle is equal to the sum of the digits on the attached arrow. [If two arrows are attached to the same circle, they each independently sum to the value in the circle.] Digits are allowed to repeat along the arrows as normally allowed by other rules.
• Cogs: Shade some cells so that each orthogonally connected area of shaded cells forms a cog: a shape with both 90° rotational and reflective symmetry. Shaded groups may not be orthogonally adjacent, but must all form a single diagonally connected network. The network of cogs must be functional, meaning there may not exist a loop consisting of an odd number of cogs. Small white dots must be shaded, and mark the center of a cog. No 2x2 area may be entirely unshaded.
• Odd cogs: Shaded cells must contain odd numbers.

Example:

Solve the example here (CTC).

Puzzle can be solved on:

• f-puzzles here

• CTC here

• Penpa+ here

The puzzle: