Logic Masters Deutschland e.V.

Eisbär (Arvid) and I have created a fresh sudoku advent calendar in which we combine a well known variant with a relatively unknown variant every day. Combining variants leads to interesting and surprising new solving techniques.

Logically solvable
All puzzles can be solved completely logically although the logic is sometimes well hidden and is inherent to the combination of restrictions that the different types offer. For that reason we have written some solving hints for most of the puzzles, published in a very tiny font. If you want to read the hints, simply copy these in a text editor and enlarge the font size.

Outside
Place the digits from 1 to 9 in every row, column and 3x3-block. Digits outside the grid have to be placed in one of the first three cells in the corresponding row or column.

Hidden Skyscrapers
A cell contains (an) arrow(s) if and only if the number in that square correctly indicates the number of skyscrapers visible in that direction. Every digit represents a skyscraper of the given height. Higher skyscrapers block lower skyscrapers.