Cat Sudoku Level 216 Hint
Look for a region whose legal cells are squeezed by two or more neighboring rows. High-level puzzles often move through exclusion, not obvious singles.
Cat Sudoku Level 216 Strategy
Expert Level 216 uses a 9x9 board with 9 colored regions. It starts without fixed cats, so the region shapes and no-touch rule do the work. Work from the tightest rows and regions before placing a cat.
Cat Sudoku Level 216 Solution
Solution cells: R1C2, R2C6, R3C4, R4C1, R5C3, R6C8, R7C5, R8C9, R9C7.