Bulbless Thermometers
Rules:
- Classic Sudoku:
Every row, column and 3x3 box must contain every number from 1 to 9.
- Bulbless Thermometers:
Along grey lines, the digits must be in ascending or descending order (i.e. the missing bulb must be at one end of the line).
- Kropki:
Two digits separated by a white dot are consecutive.
Play it online in SudokuPad.
This puzzle is also on Logic Masters Germany.