Logic Masters Deutschland e.V.

Normal and Diagonal Sudoku rules apply. Each row, column, 3x3 box and the positive diagonal (from bottom left to top right) contains each number from 1 to 9 exactly once.

The grey lines are palindromes: they are sequences of digits which read the same backward as forward (for example: 1374731). Each half of the palindromes also act like thermometers: digits increase from the ends. (for example: 14641 is valid, but 53835 is invalid, because 5 is greater than 3).

Inequality signs between two cells show which one contains the lower/higher digit.

The puzzle is also available online.