Sudoku quarterly | Fourth quarter 2019

The solution to a sudoku is a special type of magic square: On each row and in each column the entries add to the same number. In the sudoku case this number is 45.
Since only the digits 1 to 9 may be used, in the solution all nine digits appear on each row and in each column. On top of this, each of the nine blocks should also contain these nine digits.

We now offer only MAGIC Sudoku puzzles. This type of the puzzle contains one or more gray blocks.
In the solution, these gray blocks should also be magic: Each row and each column should add to 15 and all nine digits should occur.
For each week, the Sudoku on Monday has one magic block, the Sudoku on Tuesday has two magic blocks and so on. On Sunday all blocks are magic.