Cat Sudoku Level 253 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 253 Strategy
Master Level 253 uses a 10x10 board with 10 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 253 Solution
Solution cells: R1C10, R2C2, R3C6, R4C8, R5C4, R6C9, R7C5, R8C3, R9C7, R10C1.