Normal sudoku rules apply. Doppel-Dög loop: Draw an orthogonal non-branching closed loop that doesn't cross or touch itself, not even diagonally. The loop "starts" at the cell marked with the dog and is considered to be oriented in the direction indicated by the arrow (i.e. r6c6 and r6c7 are in the loop). A cell on the loop with a digit D will have a value equal to the cell D steps away along the loop in the orientation given by the arrow. Cells not on the loop will have a value equal to the digit in them. Adjacent digits (not values) along the loop must have a difference of at least 5. Values in a cage sum to the indicated total. Cells marked with a circle are not part of the loop and have a digit that equal to the count of the, up to 8, neighbouring loop cells. Clues outside the grid show the sum of the values of the loop cells in the indicated row/column.