Logic Masters Deutschland e.V.

Fog of War: much of the grid is hidden by fog. Correctly placing digits will remove the fog to reveal more of the grid. No guessing is required.

Arrow: digits along an arrow must sum to the digit in the circle.

Black Dot: digits on a black dot must have a ratio of 2:1 (there is no negative constraint).

Minimum: digits on a grey square must be smaller than any adjacent cells.

Skyscraper: digits outside the grid indicate the number of cells that can be seen in the column or row. Higher digits block lower digits.

Quadruple: digits in a white circle adjoining four cells must appear in those four cells.

German Whisper: adjacent digits on a green line must differ by at least five.

Thermometer: digits on a brown thermometer must increase in value as they move away from the thermometer bulb.

Region Sum Line: there is one blue region sum line in the grid, divided into segments by box boundaries. The values of each segment must be equal.

There is a yellow circle hidden in Box 9. The value of that cell must have the same value as the cell in the same position in Box 1. No other cell in Box 9 may be the same as the cell in the same position in Box 1.

You can try this puzzle on SudokuPad