Logic Masters Deutschland e.V.

Normal Sudoku rules apply.
Roman numerals in the green circles are the sum of the 2 diagonal cells either side of the circle. Negative roman numerals are the sum of the two cells on the negative diagonal. All other roman numerals are the sum of the two cells on the positive diagonal.
Roman numerals from 3 to 17 are:
III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII