Logic Masters Deutschland e.V.

Hello.

Normal Sudoku rules apply.

Cells separated by a single knight's move in chess may not contain the same digit.

Digits in a quad circle must appear exactly once among the four cells touched by that circle.

Additionally, no subset of digits around a quad circle may sum to another subset around the same circle.

Digits may not repeat around a quad circle!

For example:

• 3568 is invalid because (3+5=8)
• 1269 is invalid because (1+2+6=9)
• 5689 is invalid because (5+9=6+8)
• 1464 is invalid because (4=4)

Have fun.