Rules: Follow classic sudoku rules. Number in a cell with a circle tells you how many distinct digits you can find in up to 8 neighbouring
cells (sharing edge or corner). Number in a cell with a cross tells you how many distinct digits you can find in up to 4 diagonally
neighbouring cells (sharing a corner). All possible circles and crosses are drawn.
17) Counting neighbours
Rules: Follow classic sudoku rules. Number in a cell with a circle tells you how many distinct digits you can find in up to 8 neighbouring cells (sharing edge or corner). Number in a cell with a cross tells you how many distinct digits you can find in up to 4 diagonally neighbouring cells (sharing a corner). All possible circles and crosses are drawn.
http://wscwpc2018.cz/wp-content/uploads/2018/10/WSC_2018_instruction_booklet_v5.pdf