Logic Masters Deutschland e.V.

Today I'm introducing another puzzle from my naughty series. The loop that you need to construct has a dilemma: it must obey the 6-9 rule, but it mustn't touch itself; so is it naughty or not?

The rules are slightly more complex than usual, but the puzzle isn't very hard, so I hope you will have fun solving it. There is an example below which illustrates the rules.

Rules:

• Normal sudoku rules apply.
• A digit in a circle indicates exactly how many circles contain that digit. For example, if there is a 5 in any circle, then exactly 5 circles contain a 5.
• Draw a 1-cell wide loop of orthogonally connected cells. The loop cannot touch itself, not even diagonally, and must visit all circles.
• Adjacent digits along the loop must sum to at least 6 and at most 9. Digits in every pair of consecutive circles along the loop must also sum to at least 6 and at most 9.
• Cells connected by an X must sum to 10. Not all Xs are given.

Play online on SudokuPad

Example:

The following example shows a loop which fulfills all the rules of this puzzle: