Normal sudoku rules apply. From each square, draw a valid hitline moving through the centres of cells. Each hitline must occupy at least two cells. Hitlines may travel orthogonally and diagonally between cells, but may not branch, share cells, or cross themselves or each other. Digits may not repeat on a hitline. The small white clue on a square indicates the total sum of all the digits along that hitline that match their position number, with the square itself being position 1. Eg: if a hitline reads 82195 then its square would have a 7 clue, as this is the sum of 2 and 5 which are the only two digits on the line which match their position number (they are in the 2nd position and 5th position.)