Cat Sudoku Level 213 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 213 Strategy
Expert Level 213 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 213 Solution
Solution cells: R1C5, R2C1, R3C6, R4C2, R5C9, R6C3, R7C7, R8C4, R9C8.