Logic Masters Deutschland e.V.

1. Normal sudoku rules apply.

2. XV. Cells separated by an X must contain digits summing to 10; cells separated by a V must contain digits summing to 5. ALL such clues are given.

3. Thermometers. Digits must increase as they move along the thermometer away from the bulb. The thermometers in each column are the longest (or equal longest) thermometers that can be placed in the column in an upwards direction.

3. The three lines are German Whispers clues - adjacent digits along these lines must differ from their neighbours by at least 5. (The lines are colored red, blue and green to represent the three pillars of emergency response, police, fire and ambulance).

4. Somewhere in the grid are hidden three emergency phone numbers, 911 (USA), 112 (Europe), 999 (UK). Alas, the code for Australia (000) doesn't work with sudoku. These three emergency numbers may be vertical, horizontal or diagonal, and may be left to right or up and down.

You can answer the emergency call on f-puzzles.

Or in the CTC App.