Logic Masters Deutschland e.V.

Standard sudoku rules applies. Fill the grid with numbers from 1 to 9 so each digit occurs exactly once in every row, column and 3x3 box.

Every digit except one has a couple. That means every digit would sum to 5 or 10 with one of its four surrounding digits. Except one. In other words, every digit has a hidden v or x. Except one. (I really hope you can guess what it is now)

This puzzle is made by Old Miles from China. Yes, it's very easy. But can you get the flow? Normal instinct for vx starts from the small ones, but this one, the flow comes from the big ones.

This one is also an experiment. You might wonder why it can't be hidden x. Because Old Miles can't do it. (I would be really surprised if anybody actually made one.)So, hidden vx. Also, 6X6 with hidden sum 7 is feasible, But it's boring. The rule was too narrow for 9X9 but too broad for 6X6.