Cat Sudoku Level 64 Hint
Find a colored region with only a few safe cells, then compare those cells against the row and column limits.
Cat Sudoku Level 64 Strategy
Medium Level 64 uses a 8x8 board with 8 colored regions. It starts with 1 fixed cats to anchor the solve. Work from the tightest rows and regions before placing a cat.
Cat Sudoku Level 64 Solution
Solution cells: R1C3, R2C7, R3C2, R4C4, R5C8, R6C6, R7C1, R8C5.