Strong Thermo
Rules:
- Classic Sudoku:
Every row, column and 3x3 box must contain every number from 1 to 9.
- Thermometers:
Along thermometers, digits must increase from the bulb.
- Double Arrows:
The sum of the digits along a grey line is equal to the sum of the two circles at its ends.
- Counting Circles:
Any digit in a circle indicates exactly how many circles contain that digit (thermometer bulbs are included).
- Kropki:
Two digits separated by a white dot are consecutive; two digits separated by a black dot have a 1:2 ratio.
Play it online in SudokuPad.
This puzzle is also on Logic Masters Germany.