Cat Sudoku Level 211 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 211 Strategy
Expert Level 211 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 211 Solution
Solution cells: R1C6, R2C1, R3C5, R4C7, R5C9, R6C4, R7C2, R8C8, R9C3.