Logic Masters Deutschland e.V.

This puzzle was originally created for the_cogito as part of the 2023 Secret Satan puzzle exchange, and is posted here with their permission. It combines Sudoku with Tapa, and also utilizes ambiguous clues and a negative constraint on clues.

Rules:

Normal Sudoku rules apply.

Tapa: Shade some cells so that all shaded cells create a single orthogonally connected area. No 2x2 square may be entirely shaded. Cells marked with a circle are Tapa clues. These cells are always unshaded, and must have a single orthogonally connected segment of shaded cells in the (up to) 8 cells surrounding the marked cell. The digit in the marked cell gives the number of shaded cells in that segment.

An unshaded region is defined as a single orthogonally connected area of unshaded cells. A cell marked with a square is always unshaded, and the digit in that cell gives the total number of cells in the unshaded region that cell is part of. Cells may be marked with both a circle and a square.

Ambiguous clues: Cells marked with a question mark represent either a circle, a square, or both. These cells must be either a valid Tapa clue, give the number of cells in its unshaded region, or both.

NEGATIVE CONSTRAINT: All possible circles/squares/question marks are given. If a cell is not marked, it cannot be a valid Tapa clue or give the size of its unshaded region.

The shaded cells act as a German Whispers line. Any two shaded cells that are orthogonally connected must have a difference of at least 5.