Logic Masters Deutschland e.V.

Sudokus with modifier cells, which are placed according to Sudoku rules and must contain a complete set of the digits 1-9, have become a very popular variant. I personally enjoy solving puzzles like this. I noticed a certain type of logic that can/must be applied in this concept from time to time.
My goal with this puzzle is to put this "trick" in the spotlight.

Rules:

Sudoku: Fill every row, column and marked 3x3 box with the digits 1-9.

Doubler: There are nine Doubler cells in the grid, exactly one in each row, column and marked 3x3 box and filled with a complete set of the digits 1-9. Doubler cells contribute twice the value of the digit in that cell to cage totals.

Killer: In cages marked with a black dashed line digits must not repeat and the values have to add up to the total given in the top-left corner of a cage.

Odd: The cell with a grey circle has to contain an odd digit.

Have fun solving!

Sudoku on:
SudokuPad
F-Puzzles