A question mark made up from 9 partly overlapping (not box-wise) Sudoku's.
Overlapping areas are clueless.
A 10th clueless Sudoku is colored light yellow and the orange dot is the center box.
The first one is easy to solve: only box/row/column eliminations and hidden/naked singles needed.
The second one is more difficult (moderate). Techniques to be used are:
- box --> row/column elimination and vv
- naked/hidden pairs/triplets/...Â
Hajime 17-may-2018