Logic Masters Deutschland e.V.

Rules:

Fill the central 9x9 grid with digits 1-9 so that no digit repeats in any row, column, or 3x3 box.

A digit N in the central 9x9 grid represents a skyscraper of height N standing on top of it. A skyscraper of height N hides skyscrapers of height <N behind it in the line of sight.

A cell surrounding the central 9x9 grid contains the number of skyscrapers that you can see from its direction along the adjacent row/column.

A clue outside the 11x11 grid gives the sum of first X digits from its direction along the adjacent row/column, where X is the digit in the cell adjacent to the clue.

Try it on the CTC app.

Puzzle: