Suguru

Medium suguru expands to an 8×8 grid with cages up to 5 cells. Fewer cells are given, so adjacency elimination alone won't solve the puzzle. You need hidden singles: when a digit can only go in one cell within its cage, it must go there, even if that cell has other candidates.

The larger grid means more neighbors per cell and more cages interacting at boundaries. Keeping track of candidates mentally gets harder. Use notes mode to write them down. The auto-candidates feature does the bookkeeping for you.

When medium feels routine, move to hard.