Logic Masters Deutschland e.V.

Fill in an empty 9x9 Sudoku grid, using the following clues:

1) Apart from normal Sudoku rules, the puzzle also has at least one of the following constraints: anti-knight, anti-king, disjoint groups.
2) One of the 9-cell diagonals contains all the digits from 1 to 9. There is exactly one parity change in the sequence of the digits on that diagonal.
3) One of the even-numbered 3x3 boxes has the following property: odd digits within the box cannot touch each other orthogonally.
4) The digits on the 4-cell diagonal starting at r1c6 have a sum of either 5 or 35.
5) In row 5, the first three digits sum to the same number as the last three digits.
6) In column 6, there is exactly one set of 3 consecutive cells of the same parity.
7) If r4c1 is lower than 5, then the middle squares of boxes 1, 5 and 9 all contain the same digit. If r4c1 is greater than 5, then the middle squares of boxes 3, 5 and 7 all contain the same digit.
8) If the 1 of column 3 is in box 4, then there is exactly one 3x3 box, where even digits do not touch each other orthogonally.
9) If r7c2 is 7 or less, then r8c2 is lower than both r5c1 and r9c9.
10) R1c4 and r4c1 contain different digits of the same parity. The same is true for r5c5 and r9c6.
11) One of the digits in the domino r8c4, r9c4 appears in r7c8.
12) R3c6 is lower than r4c2.
13) R3c8 is two, three or nine times bigger than the digit in r4c4.

Click here to play on f-puzzles (although you can actually play starting with an empty grid anywhere you like!)