Logic Masters Deutschland e.V.

Normal Sudoku rules apply. Each row, column, and 3x3 box contains each number from 1 to 9 exactly once.

XV Sudoku rules apply. Orthogonally adjacent cells with the sum of 10 are marked with an X. Not all possible pairs are marked!

Arrow Sudoku rules apply. Digits along an arrow in the grid must sum to the digit in its circle. Digits may repeat along the arrows. Two-digit numbers must be read from left to right or from top to bottom.

Additionally each arrow sum has a pair in the grid. So for example if you find out that an arrow is 15, then must be an other arrow (exactly one) in the grid which sums up to 15.

The puzzle is also available online.