Arrow Sudoku...

What are people's thoughts on arrow sudoku?

At the moment I'm finding them to be one of the most interesting sudoku variants that I have come across, although there are very few of them about out there I have to say.

Anyone know a good source of these puzzles...

If you haven't come across them, then the rules are the same as normal sudoku except that there are arrows added to the sudoku grid. These show you a circled cell, which is the sum total of a region of cells along the path of the arrow that sum to that. If you see a sample one then it will be obvious what it means, perhaps hard to visualise otherwise.

Anyway it is interesting because at the start you don't know the total of the sum region or the digits in the sum region, however you can derive a surprising amount of information just from the shape and length of the arrows and as you go through reducing options it is surprising how much fun it is and how patterns emerge whilst you solve... arrow sudoku is great fun