Hard Killer Sudoku 12X12

Tips on solving a challenging 12x12 Killer Sudoku: 

1. Start with the cross-hatching technique. Fill in the most obvious cells with larger numbers.
2. Identify additional blocks (outlined with dashed lines) that contain 1 or 2 empty cells. Sum up the known numbers in this block and subtract from the number in the top-left corner to find the sum of the numbers remaining empty in this block.
3. Find cells at the intersection of rows and columns with the highest number of known numbers. These cells usually contain only 1 or 2 candidates, making it easy to fill in with a larger number.
4. Try combining different strategies, and in extreme cases, apply advanced Sudoku techniques.
5. Complete the Sudoku puzzle and let us know how it went. We are eagerly awaiting your feedback.

Wishing you success in solving the challenging 12x12 Killer Sudoku!