Logic Masters Deutschland e.V.

Normal sudoku rules do NOT apply.

Place into each row, column, and box the digit 1 twice, 9 once, and six of the seven digits from 2 to 8, while one digit from 2 to 8 (to be determined by the solver) does not appear in the grid at all.

Each row and column contains either a double sandwich, with the 9 between the two 1s, or a club sandwich, with the 9 to one side of the two 1s. In a double sandwich row or column, the outside clue gives the identical sum of digits between the 9 and the two 1s, i.e. 8 for 1[35]9[8]1. In a club sandwich row or column, the outside clue gives the sum of digits between the 9 and the 1 further from it, i. e. 8 for 1[341]9 (note that the middle 1 is always included in this sum).

Every double sandwich row and column must have identical sum for the two sandwich halves, even if no outside clue is given.

The marked diagonal sums to 34.

Solve on Sudokupad