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.

The circle indicates the digit inside the circle is the sum of some of the four neighboring digits, or in other words, cells who share a border with the circle cell.

All possible circles are given.

This is in the between period puzzle. My focus shift more to the aesthetic part. There’s always a key symbol, in later days, structure that stand out. In this puzzle, negative restraint makes it looks random. But the centre cross is still kind of noticeable.

Now is what I thought then. I did not expect the rule to be this clean. I was going to make a 4 neighbor mean. But later i found the symmetry of 5, which made it impossible to empty a grid. Plus the add difficulty. N sum needs two small, while mean needs one big one small, which made it harder to found the break in. The negative restraint is good enough. One should pick up his speed in the end period. But the fact shows, 4 neighbor cell are pointless

How did I solve it then? Why i have no memory. Probably because the two choice let me down, which later becomes the prototype for placing, which have way more choices. I think this idea comes from maybe a neighbor sum variant, which i don’t recall, that’s way too long ago. Old miles also made one with the same idea, which i can’t solve, so i guess this probably might be the last time Old Miles and I try a neighbor cell variant